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Posted: 5/18/2008 4:00:10 PM EST
[Last Edit: TaylorWSO]
2012 Update: Added the new AR10A info

Since this has become a tacked thread feel free to post any info you might have on the AR10. If you want history/and information/ Tech manuals I would suggest Armalite's Library
Much of this info I stole or gathered from AR10 users but its all correct AFAIK. If you want answers directly form Armalite, see the FAQ in their industry forum

1. Why does everyone make a big deal of calling my semi 308 a "AR10"?
The reason is because Armalite has spent a lot of money producing the AR-10 when no-one else would. They have spent a lot of time building the name and reputation not to just have someone else use it to describe their rifle. Another problem stems from the fact that many people refer to problems with their "semi 308" as a "AR-10 problems". This misnomer leads people to believe that the AR-10 is a poorly built rifle with a lot of problems, when in fact, the opposite is true.
Even if you don't agree at least you should understand, you wouldn't order a "Coke" if you wanted a "Pepsi", you also wouldn't order a "Pepsi Coke"
Yes its a big deal. See trademark tacked topic

2.Can DPMS/POF/KAC/RRA/ Larue Tactical upper be put on Armalite lowers
NO-see pics below. The only uppers that can be put on Armalite lowers are Noveske, Eagle Arms, or Armalite witht the "45" cut on the upper reciver vs the "rounded" DPMS style reciever . The new (11/08) LT uppers are based off the Kac design and the pins will not work even though the upper has the "45" style upper.
3. Can other (DPMS) mags be used in Armalite rifles
YES (1/2012); BUT-You can only use Armalite proprietary GEN-II mags, a modified M14 mag (GEN-1), or a unmodified M14 mag held in the receiver with the sling in a AR10B. The new AR-10 A can use the old style mags. See post below for more mag information and other 308 Semi platforms

See also Tech Note http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%20101%20%20AR-10A%20AR-10B%20%20M15%20COMPONENTS%20120109%20Rev%201%20FINAL.pdf
4. Can I use AR15 parts in the AR10-
YES- see post below for the actual interchangeability

5. Can I use a AR15 lower with 308 upper?
NO- the 308 is too long to fit in a 223 magwell. MGI is working on a magwell that will fit on a 223 lower with a 308 upper. See pics below
6. Will a AR15 (CAR) stock fit on a AR10?
YES (with caveats) you will need to use either the carbine AR15 buffer tube with a AR10 spring and a shorter (slash's) AR-10 buffer (for the longer AR10 BCG), OR put a AR15 stock on the AR10 buffer tube BUT it will not collapse all the way-see below for pics. The A2 stocks are the same, the AR10 rifle buffer is a little shorter in the AR10 rifle-see pics below
7. Can I build a AR10 like a AR15
Yes they are basically the same parts except you will need bigger tools (vice blocks). Armalite even offers a kits part #GSK10A4 (minus lower receiver-call for info) just for this purpose. Note: you can use a regular AR15 barrel wrench to take off a standard AR10 delta ring, but will need a larger FF wrench to tighten the large AR10 FF barrel nuts
8. Who can build me a "custom AR10 rifle"
GAP or Noveske and Mike Bykowski, are the current builders beside Armalite. They are pricey but you will hear nothing but good things from both companies

9. Is the chamber on an AR10 .308 or 7.62?
From Armalite: All of our AR-10 .308's are NATO chambered and will accept both 7.62 and .308 ammo. The AR-10 can shoot 308 OR 7.62 NATO.

The difference between .308 and 7.62 is chamber size, slight pressure differences due to powder burn rates, not external case size. Both cases will have the same external dimensions while the .308 has a pressure of 60Kish PSI vice 50-55 CUP psi for NATO**. NOTE: This is not the same as 5.56/.223 rule of thumb. The NATO chambers have greater tolerances to help with reliable functioning of military ammo. The NATO chamber is ever so slightly longer at .013". This is significant in that for reloading purposes, 308 brass will stretch more in a military chamber upon firing, thereby reducing the life of the brass and possibly promoting case head separation. But that additional chamber length will allow a round to chamber in an incredibly dirty weapon, which is a requirement for military applications. Also be aware this is why mil NATO brass is thicker vice 308 commercial brass. You will also see this "thicker brass fact" posted about 5.56/.223 brass which is a fallacy.
**As a side note the reason the pressure issue is confusing is becuase the military measured 7.62 NATO chamber pressure (PSI) via CUP (in the 40s) vice the normal commercial rating of PSI  measured (now) with electronic means. You will see many cling to the 50-55K PSI figure for 7.62 Nato becuase that is what the old Army TMs have in them. Since there is no conversion for the CUP measurement to the newer electronic measured PSI, they are two different numbers i.e no direct comparison. Many people will assume the CUP PSI is the same as SAAMI/Commercial PSI. It is not. Commercial PSI is derived from the direct pressure in the chamber through electronic means (piezo transducer or strain gauges). CUP is a crush measurement of a copper slug that has been fired, again not the same test.
That means any newer weapon will be able to fire 308 Commercial ammo as manfs would not let them out the door if they could not, due to liability. Don't believe me, run the numbers/powders in any internal ballistics calculator and they will all be close to the 60K mark. BTW the proof load for the 308 commercial is 75K PSI, so don't worry about the 60K.
Here a good discussion with some testing  not myth about how the pressures are basically the same despite the wives tales



•AR-10 NATO – 1.633-1.638 (stainless steel, chrome moly, and chrome lined barrels) "
308 Winchester (SAAMI) Headspace
GO - 1.6300"
NOGO - 1.6340"
FIELD - 1.6380"
7.62 NATO (Military) Headspace
GO - 1.6350"
NOGO - 1.6405"
FIELD - 1.6455"
Note that the military chamber would fail a NO GO check with a SAAMI gauge, but pass a FIELD check using the proper military gauges.

10. Where can I buy a AR-10 lower/parts. I don't see them around.
You can get many parts right of the EE. DSG arms or 762 SASS is also a stocking dealer (parts/lowers), as there are others I'm sure . If you want to order an AR-10 rifle or lower, have your FFL call and get one direct from Armalite. CWS now has AR10 lowers, June 09 Rainierarms has AR10 lowers

11. What are the differences between the Armalite Tactical and Match triggers?
The mechanisms are based on the same castings. the difference is a different pre-load on the disconnecter spring and tuning the second stage back by stoning the upper hammer hook in a manner similar to the M14
The mechanisms are based on the same basic design. The difference is the location and shape of the trigger bow, different weights of pull, and tuning the second stage hook in a manner similar to the M14.
The NM trigger bow is mounted farther forward for better trigger finger placement, while the Tactical Two-Stage trigger has the same bow as the usual single stage trigger of the M-16. The trigger weight of the installed NM trigger is approximately 2 pounds lighter than the Tactical Two-Stage trigger, and the NM trigger is tuned so that the shooter won’t be distracted by movement in the second stage.
The two triggers serve different purposes, so a single standard isn’t practical. While NM triggers are outstanding for match use and for casual shooting, the officials of many Police or Military organizations require a trigger of higher weight.
The 10309000 Tactical 2 Stage Trigger was standard in AR-10's and M-15's around August 2006.

12. How good is Armalite's customer service?
I doubt you will find better in the industry. There have been multiple threads on this subject of very satisfied customers. They usually bend over backwards to help you, as long as you are well-mannered and reasonable I've never heard of anyone being turned away.

13. Why are mags more expensive than DPMS?
Initially Armalite spent a lot of money getting the tooling/research to build the new Gen-II mags and the initial price reflected this. Armalite has had, and is continuing to offer a "basic load" mag sale that put them at the same price as DPMS mags. The plus is that they offer a true 20 rd mag, not just 19, and they also offer a 25 round mag thats not a "hack job" you normally see with 308 mags.
EDIT as of 1/12 you can stop bitching about the mag "issue" The AR10A will work with the old style/PMAGS mags

14. Why is the Armalite more expensive than the DPMS?
Armalite has been in the game a lot longer and have added many upgrades over the years (same as the AR-15 history) They also offer features the DPMS rifles don't have (chromed lined barrels, lifetime warranty,better triggers, forged receivers, and MOA guarantees). These extras cost money- If they are not important to you then get whichever you want. You can usually find many better deals than just MSRP by building it yourself or buying the parts separately (remember the warranty thought). The mid-length gas system is more reliable than the 6" "shorty" carbine gas system. See the spread sheet below for more specifics.
15. Can I use a AR15 gas tube on the AR10?
Yes BUT realize the AR10 gas tubes are about .2" longer than the AR15 tubes. They can be used in a pinch but might cause a loss of gas/short stroking. They are longer to make up for the bigger (wider) barrel nut that Armalite uses on the larger AR10. Mid length gas tube is 12.060"and rifle gas tubes 15.500" Note the gas tubes on a DPMS/KAC are regular AR15 gas tubes.
16. What are the threads on the AR10 for a FS or MB?

most 308's are threaded 5/8-24
17. What BUIS works on the AR10?
The AR10 uppers are about .1" higher over bore than the AR15 and require a higher front gas block BUIS. You can use any rear AR15 BUIS, see "BUIS Information" below.
AR-10 top of gas block and upper receiver rail – top of gas block is .398 (+/- .010) lower than top of upper receiver.

18. What FF tubes can I use on my AR10? Will a AR15 tube work?
You cannot use a AR15 tube because of the larger barrel nut on the 10. You also cannot use DPMS FF tubes as the barrel nut threads are different. Armalite uses 18tpi threads and DPMS/KAC use 16tpi. You can use a KAC FF tube on a AR10 but it will be longer than a AR10 FF tube and there "may" be problems with the gas block You can use early KAC fiberglass/carbon fiber FF tubes with an Armalite AR10T barrel nut, but the overall handguard length will be about 1/4" shorter than a standard Armalite AR10 FF tube (due to Knight and DPMS using an AR-15 rifle length gas tube).
19. Whats the difference between Eagle Arms and Armalite?
They are exactly the same parts. Armalite used to use only "Armalite" lowers for actual factory built guns and sold "Eagle Arms" as stripped lowers/uppers. This was to differentiate between the two different warranties, Armalites have a lifetime warranty and EA have a 1 year only warranty. Armalite has started to offer "Armalite" stripped lowers (spring 08) for sale
20. What range should I zero my AR10A2?
After asking this question myself I did a little research. The A2 AR10 sights are calibrated for the NATO 7.62 drops. So to use it correctly, set it on the 200 graduation and zero it in at 200 yards or 45 yards. Now you can use the sight to its full potential. You can use 45 yards since with the 20" barrel and 2700FPS NATO 147gr FMJ the round will cross at both points
21. What is the difference in the PRS for the AR10 and the AR15? I know the spring and the buffer, but anything else?
The movable cheek piece on the AR-10 version is shorter to clear the AR-10's longer charging handle. It has 4" of clearance from receiver to cheek piece, unlike the 3.5" on the AR15 version-see pic below
22. What lowers are available for the AR-10 besides Armalite?
As of now (fall 08) there are 4 choices available besides armalite. You can get a Eagle Arms lower that is made by Armalite, you can get a Noveske N6 lower and Aero precision offers a lower (all forged). They will all work with the AR-10 parts and mags. CWS has the aero precision lowers. CMMG now has a billet lower that will work with armalite style uppers. They are also making a Armalite lower that uses DPMS mags and possibly the G3 mags. Larue Tactical makes a lower (OSR 7.62) that looks like it will work but the takedown pins are too big at .281 (based off the SR25/M110 pins)"  
As of Jan 2012 Armalite will produce two different lowers the AR10B and the AR10A. Each will have to have own uppers- The AR10A will take the PMAGS see Tech Note 101

23. WTF the guy at Armalite said I couldn't use my (insert ammo brand here) in the rifle, shouldn't it shoot everything
From Armalite: The AR-10 will work fine with all high quality 7.62mm ammo from 147 to 175 (it's not loaded outside those limits), and much handloaded ammo.
The problem is that not all ammo is the same. Short stroking is a sign that there isn't enough gas being delivered, or that it's being cut off by poorly assembled gas blocks, etc.
A common problem is that remanf or handloaded ammo is frequently not to NATO specs. Similarly, some surplus ammo just doesn't cut it, especially overseas import surplus.
The point being is what "you think" this "good ammo" could be garbage. If you are having problems buy a box of the good stuff in bullets weights above, try it and see if its the ammo or rifle. There is a much finer line to walk with the AR10 and 7.62 ammo than the AR15. Read the Tech note 75
As a last reminder, SURPLUS NATO ammo is not the same as NATO ammo. It was surplus'd for a reason. As a note overseas surplus ammo usually does not have as much pressure as LC Nato ammo or commercial 308 (commonly believed to be loaded to suit the FAL).

24 What ammo do I need to stay away from/whats good
Although each rifle will vary, some know problem causers: some lots of SA (south African) it has caused problems in FALs and M1A's, OFV (Indian) although OFV from the 70's is "rumored" to work, I would never use it, as there are many Kaboomed rifles on the net from OFV, Ultramax, RG has some lot problems with underpower ammo.
Good ammo, PORT/AUSSIE/FED (fed has soft brass causing the ejector to stick), MEN, DAG, Blackhills, WIN and of course LC in the 2000-2003 lots, Not much info on the newer 2005+ "surplus'd" lots
One thing to note is that surplus from the earlier years is not the same as surplus you can find now. The newer LC stuff has had the bullets pulled and reloaded with powder to get around the anti-surplus laws, some of it may be from a lot that failed inspection for the US mil.
Also to add soft brass causes problems in any S/A rifle due to the higher pressures at extraction and all the moving parts/pressures in the upper under firing conditions, unlike a bolt. What does this mean? Soft brass will burr easily, clogging up your weapon. I usually get away with it, like shooting fed brass once, but I will not use it for reloads. This extraction under pressure will cause the extractor to clog, and also the ejector when the brass flows a little and the camming action rips a few pieces into the ejector. I love fed match ammo, but you need to be aware of this and clean/inspect the ejectors/extractors more closely.
7.62 AMMO list
25. What gas block can I use? What size gas block do I need?
The T models use a .875" gas block (the 16" T use a .750" block though), and the others use the standard .750" gas block. You can use a lo-pro AR15 gas block but it obviously needs to be the correct diameter. Realize that if you remove the handguards and replace the FSB with a gas block for a Free Float tube, you could encounter spacing problems when the handguard cap was removed. Many people have gotten into trouble when seating a gas block directly to the shoulder of the barrel and not allowing the space for the removed handguard cap. Some companies make gas blocks specifically for this with a .3" vs .280" gas hole from shoulder. Realize on the T models the mounting area for the gas block is limited, so longer gas blocks will work, but could have unsupported area.

26 How are the new AR-10s different from older ones?
There have been three generations of AR-10 rifles. ArmaLite’s AR-10B series rifles art the third series in the historic family. The first, designated AR-10, was designed in the late 1950s and entered production in the early 1960s. Only about 10,000 rifles were produced. The second series, the AR-10A, was an improved version that didn’t enter production. The third series, ArmaLite’s new AR-10B, is the latest and most up to date. The series is normally referred to with the shorter AR-10 designation with no reference to the B. Added, even the new AR10 series the current Armalite is producing has had upgrades/mods. Armalite like to keep making it better for some reason. AR10A has been added in 2012 using the old style (50s) Armalite mags

Five models of the AR-10B series exist: (note the AR10A has been released as of 2012. AR10A will be the same as the B but use the old style(1950s) mags. See tech note 101 on armalites website.
––AR-10B is the base model of the new ArmaLite line. It is loosely patterned after early 1960 era rifles, and is produced largely for nostalgic reasons. The charging handle looks like an upside down trigger and is located at the front of the carrying handle. It bears early M16 furniture in a brown epoxy finish and a rear sight elevation window at the rear of the carry handle.
––AR-10A2 is the Infantry model, virtually identical to the latest M16A2 Service Rifle, but scaled up for the 308/7.62 cartridge.
––AR-10(T) is the target model featuring a 20 or 24 inch long medium weight target barrel.
––AR-10A4 is a flexible combination of the AR-10A2 and the AR-10(T). It is generally identical to the AR-10A2 except that the upper receiver and gas block are manufactured with the "Picatinny rail” sight mounting surfaces of the AR-10(T). Removable metallic or telescopic sights are optional.
–– SuperSASS is the most versatile AR-10 rifle inasmuch as its variable gas system is adaptable to a sound suppressor.
–– Most variations of rifle have matching carbines except for the collapsible buttstocks and shorter barrels.

27 My bolt wiggles/has more slop than my AR15 is this normal?
According to Armalite it is fine for this to happen. The AR10 can have more slop due to the bigger volume of gas. The AR15 "stand the BCG on end/ see if the bolt moves" does not apply to the AR10. Armalite has even said it will run without them, Although I would not try this. So what the answer, if it shoots then enjoy. If you have any gas problems and loose rings, replace the rings. I have a 10K+ A2 that has yet to have the rings replaced. YMMV
28 How do I take the free float handguard off?
Its very easy. Mount the upper in a vice, 2 blocks of wood or plastic with the upper on its side works if you dont have deticated upper blocks. Take a strap wrench and remove the nut from the back of the tube. Be adviseed that they put that thing on there tight. A quick blast with a heat gun or torch can help to loosen it up. Once the nut is off just pull the tube (forward) off the barrel nut. This can also be very tight, but wiggle and pull and it will remove easily. You do not need to take the screws out of the side/bottom of the tube, just the nut on the end of the tube. Obvioulsy you will need to remove the gas block
29 Will Magpul mags work in the AR10?
YES in the AR10A released in 2012

Kindof in the AR10B.
Although they were not designed for the AR10, they can be made to work in th AR10B. I'm not saying they should, just saying they can. To make them work you have to cut (dremmel) the front/top of the mag so it will sit high enough to feed. You will be removing material to get around the mag stop shelf that the AR-10 upper has. You must also sand the sides/front and back so that it will fit the magwell. It can be done and they will work, but at a price. After modding one, I found the plastic too thin to be field worthy, Removing material in a heavy mag is a bad idea if you want to depend on them. While the PMAGS are defiantly great mags, I cannot justify moving away from a reliable steel Gen 2 mag.
30 What are the weights of the mags

Gen 2 Mag empty 8.4 oz
Gen 2 20 rds 147 gr ammo 1 lbs 7.8 oz
308 PMAG 5.6oz w/o cover
25 round 9.5 oz
25 with 147 gr 1lb 15oz

31 Whats the difference in a AR10B family and the AR10A that was just released in 2012?
The AR-10A family of ArmaLite® firearms is functionally identical to our AR-10B family. Operation, controls, and maintenance are the same. However, the AR-10A family is designed to accept early ArmaLite AR-10 "Waffle” magazines and good quality magazines copied from them, instead of ArmaLite’s proprietary steel magazines that are used in our AR-10B family. Neither family of firearms will function correctly with the other family’s magazines. Some components of our AR-10A firearms are unique to that family. For example, the AR-10A Bolt Stop, Magazine Catch, Upper Receiver, and Lower Receiver are not the same as those in our AR-10Bs.
read this http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%20101%20%20AR-10A%20AR-10B%20%20M15%20COMPONENTS%20120109%20Rev%201%20FINAL.pdf



Link Posted: 5/18/2008 4:00:16 PM EST
[Last Edit: TaylorWSO] [#1]
AR15 lower and AR10 upper, no it won't work

Other lowers

CMMG billet 11/08

Aero precision



Armalite AR10 magnum

Eagle Arms
Link Posted: 5/18/2008 4:00:21 PM EST
[Last Edit: TaylorWSO] [#2]
Since this has become a tacked thread feel free to post any info you might have on the AR10. If you want history/and information/ Tech manuals I would suggest Armalite's Library
Much of this info I stole or gathered from AR10 users but its all correct AFAIK.  
Stocks and the AR10

To use a CAR AR15 stock/extension tube/buffer on a AR10, you need Slash's buffer and a AR10 spring. Armalite now makes their CAR stocks mil spec diameter so you can use AR15 stocks over their buffer extensions, BUT they "might" not collapse/stick out too far since they are 1' longer than a AR15 buffer tube-see pic below.
CAR Extension measurements:
OLD Factory Armalite AR10 extension: 8" External, 7 3/4" internal, commercial diameter 1.171"

NEW '07 Factory Armalite AR10 extension 8" external, 7 3/4"" internal, MIL spec diameter 1.145"

VLTOR AR 15 extension : 7 1/4" external, 7"internal, mil diameter 1.145"

Magpul 93B extension: 7 1/2" external, 7" internal, diameter doesn't matter

AR15 commercial extension: 8" external, 7" internal commercial diameter 1.171"

AR15 commercial extension 7 3/4" external, 7" internal, commercial diameter 1.171"
As you can see many of the AR15 tubes have different external lengths but they all have 7" internal lengths.
You can use commercial diameter AR15 stocks on the pre-07 factory Armalite CAR tubes but they won't collapse all the way, if they do, you will have the extension in your shoulder since its 1" longer than a AR15 buffer tube. The Armalite factory AR10 CAR stock will work on commercial AR15 tubes. AR15 mil spec stocks will work on the new AR10 buffer tubes but again they might not collapse or collapse too far.

The rifle extension on the AR15 A2 stock is the same as the AR10 A2 rifle extension.
An AR15 commercial stock on a AR10 CAR tube:

Stolen from Magpul


Rifle buffers:

As you can tell the AR10 buffer is shorter to accommodate the longer AR10 BCG. You can also make a AR10 buffer from a AR15 buffer, Take it apart and cut it down 3/4". You have to remove the aluminum spacer and add a smaller weight in its place. This will bring the weight up to a correct 5.4oz. See Randall's picture below.
The rifle extension on the AR15 A2 stock is the same as the AR10 A2 rifle extension.

Rifle springs. As you can tell the AR10 is 1" longer than the AR15 spring at 13.75"

CAR springs/buffers:
From top down


AR15 H

Slash's (uses AR10 spring)

Armalite AR10 factory H buffer: The ArmaLite OEM AR10 carbine buffers are marked "H", but they are not standard weight AR15 H buffers. (uses AR10 Spring)

This is Slash's table I stole. Really good info. Really good buffers, I would highly recommend them. Here's where he sells [/url][url=http://them[/url]

Sights/BUIS. what works"
The AR10 flatop is .1" higher over bore than the AR15 flatop. This means you can't use regular AR15 flip-sights on the frontgas block, unless the front sight has an extra long post (which is notreally a good idea). You can get front sights that are specificallymade for the AR10. GG&G makes a great set (I own a set), andArmalite sells a "non-flip" front site that attaches to the gas block.Midwest industries also sells a front sight, MCTAR-10-AFFG. Once youget the correct front sight, you can use any rear sight.
If you have a continuous free float rail, then you can use AR15sights because they are co-planer. Be aware that AR15 elevations (A2BUIS) will not align with the 308 bullet drops. The AR10 handle/A2sights that Armalites sells are actually calibrated for the 7.26 NATOballistics.


MISC info about the AR10

From Randall:

AR-10 gas tubes of the same type (mid-length or rifle-length) are basically 3/16" longer than similar tubes for AR-15's. They also have additional bend put into the "kink" that's usually there. This is to account for the larger diameter bolt carrier and it's higher location of the gas key from the bore centerline.
From Armalite tech note 6
GAS TUBE: .The AR-10 gas tube is .240 inch longer than the M-16 gas tube used on the M-16 or the SR-25 to allow use of standard handguards and the spring loaded slip ring of the AR-10A2 and -A4.
The length of the carbine gas tube is 11 1/2" for the standard 8" (midlenght handguard).
Barrel nuts Armalite uses 18tpi  DPMS uses 16tpi. Thats why you can't switch them between rifles.

AR10 lower/AR15 parts interchangeability:
M-15 Lower Half Parts

1 *Pistol grip, black EL0030 $5.00

2 *Ejector/Safety spring (2 per rifle) EB0110 $.75

3 *Safety detent EL0060 $1.00

4 *Buttstock screw (A2) EL0090 $3.00

5 *Buttstock Assembly (A2), black EL0110 $35.00

5 *Buttstock Assembly (A2), green EG0020 $40.00

6 *Buttstock spacer EL0130 $1.50

7 *Detent spring (2 per rifle) EL0140 $.75

8 *Detent (2 per rifle) EL0150 $.75

9 Takedown pin EL0160 $5.00

10 Pivot pin EL0170 $5.00

11 Buffer EL0180 $14.00

12 Buffer spring EL0210 $2.50

13 *Bolt stop pin EL0220 $.50

14 Bolt stop EL0230 $8.00

15 *Bolt stop plunger EL0240 $1.25

16 *Bolt stop spring EL0250 $.75

17 Mag catch EL0260 $6.00

18 *Mag catch button (aluminum) EL0270 $3.75

19 *Mag catch spring EL0280 $.75

20 * Safety selector EL0290 $10.00

21 * Rifle receiver extension EL0370 $20.50

22 * Disconnector EL0330 $6.00

23 * Disconnector spring EL0340 $.75

24 * Standard Trigger EL0350 $15.00

25 * Trigger spring EL0360 $1.50

26 * Hammer EL0310 $22.00

27 * Hammer spring EL0320 $1.50

28 * Hammer and trigger pin EL0300 $1.25

29 * Trigger guard pin EL0430 $.35

30 * Trigger guard assembly EL0380 $8.00

31 * Buffer detent EL0190 $1.00

32 * Buffer detent spring EL0200 $1.00

Standard Trigger Group EMK005 $35.00

FORWARD ASSIST AR-10 forward assist (10005001KIT - $14.00) NOT THE SAME AS THE ar15
The pins and bolt catches are not interchangeable due to the wider lower (308 magwell) of the AR10. The mag catches can be used but they will not engage the push button all the way.
As a note the AR10 mag catch has a slight "bend" to it. It allows the catch to set farther in the magwell, this catches the non-parallel mag sidewalls better as it sets in the parrlele walls of the mag well.

10 right, 15 left, notice the slight bend.

you can see how it kinda bends into the magwell, pic by skulpin

Note: the older bolt carrier groups have to have a thinner hammer (.196") than a regular AR15 hammer. The 98-00 bolt carriers only had a thin channel (.3") that would not function with a regular width hammer.  The newer BCGs have a .5" channel that will work with all triggers AFAIK. See pics below.

MAGS in the 308 platforms

Armalite uses both. The AR10B family uses "M14 style" mags, with their latest proprietary "Gen II" Mags. They were forced to use the modified (plunger/follower) M14 mags because of the AWB. Some of the home-brew modified mags were pawned off as "Original Armalite" mags and they wouldn't run for anything. This has been a sore spot with the AR10; getting a bad rap for crappy home modded mags. The mags that Armalite factory modifies work just fine. The "GEN II" mags work even better without the plunger.

The AR10 A uses the PMAGs/Old style armalite mgas
RRA- uses the FAL mags which has been noted to not work in a rotating bolt platform http://www.ar15.com/forums/topic.html?b=2&f=27&t=149407 , such as the AR10. Bushmaster tried it and failed. The RRA is currently (feb 08) out but few range reports. I believe if anyone can make a FAL mag run its RRA.
DPMS/KAC/POF/Larue/Fulton=Armalite original waffle mags- some people are having problem with some of the DPMS mags. But overall I think the SR25 design is a great mag. *Note the DPMS SR25 pattern mags are not from the same place as the KAC SR-25 mags. KAC mags are 50$+ if you can find them. The DPMS seem to work just fine, but the few reports I mentioned are from DPMS mags. DPMS mags will only hold 19 rounds BTW. Ive heard you can modify the follower to accept more-again only rumors since I don't own this platform.
Bushmaster MRC (old Cobb Mfg) uses a modular lower that uses G3 mags. This could/could not be a great idea because of the availability of the mags. They are cheap/plentiful right now, but who knows for how long. Most countries have gotten rid of the g3 and mags are no longer being produced. If you can get a few hundred it might make up for the price of the platform. Lets see if they can get this 308 version running.
Bushmater used the FAL mag and has since ceased production. RRA is giving it a go. See above.
HK 417- The prototyped used G3 mags but the latest version uses a propitiatory plastic mag-Good luck getting it.
The bottom line, the mags have always been a weak link in any S/A platform. Armalites Gen 2 are a little more expensive than the DPMS but deals can be had on both. Armalite is currently selling them on par with the DPMS mags.
As od 2012 you can get "both".
Whatever you get buy cheap (if you can) and STACK DEEP the election is nearly upon us. yep we're fucked
Some changes I've noticed. The first modified M14 mags had long feed lips. Apparently this caused a few rifles to have feeding problems. A couple of years after the AR10 release, Armalite started cutting down the feed lips. I guess it helps feeding by allowing the 308 round to get up the "steeper" barrel extension, vs the M14 chamber which doesn't have the multiple lucking lugs in the way. The last pic is of the GEN2 mag which replaces the dreaded pin with a non-binding follower

Bolt Carrier Groups (BCG)
Here are some changes of the BCG over the years. As mentioned above, the 98-00 year model had a thin notch for the hammer. The middle aged version will work with all hammers. The newest version has had the bottom of the BCG milled to form a shallow "V". This allows the BCG to cycle without pressing down on the rounds in the mag as much providing for fewer malfunctions.

This is what a "new" 2 spring improved extractor looks like. Pics from Ar15barrels


Link Posted: 5/18/2008 4:00:26 PM EST
[Last Edit: TaylorWSO] [#3]
Other 308 AR Information:

Bushmaster- Bought the rights to the RRA and produced it from about 2004ish-2006 ish. They had a few problems with broken bolts (hardening problems) and basically couldn't make any money off of it. It uses FAL mags and not interchangeable with any other 308's

RRA now produces the LAR-8. The same version as the bushmaster but with "upgrades", uses FAL mags. It was release Feb 2008.

KAC/DPMS/Fulton/POF/pattern rifles.

Basically they all use the same Original Armalite/KAC pattern mag. The main difference is in the upper. POF uses a piston. Fulton Titan is a "customized" (read expensive) makeover using DPMS parts with a Kreiger barrel and match trigger.

LWRC SABR: a proprietary upper/lower that uses DPMS mags. They have a piston/side charging upper thats pretty nice. They are also rumored to make a piston conversion for the DPMS lowers

COBB/bushmaster: Proprietary upper/lower. Cobb started with a 308 that uses HK91 mags and a 30-06 version that uses BAR mags. Sold the design to Bushmaster in 2006.

HK= proprietary mags

KAC is KAC, and DPMS is based off of it.

DPMS- based off the KAC- not chromelined and triggers usually suck. Some people love them and have gotten a good gun. Some have had to get a new barrel and work the triggers.

Noveske uses Armalite lowers/uppers, Noveske is now making their own lowers with their own name, will work with Armalite uppers but are "off-list" and not banned in CA. Nice but pricey which many will pay for living behing enemy lines

Hesse/Vulcan are based on the Armalite lower but some versions use DPMS mags and some use the M14 pattern mags. You can find them that use DPMS mags and Armalite uppers. The Hesse Har-25 uses Armalite unmodified upper.
Hesse/Vulcan lowers can be used with AR10 upper but they use DPMS mags. You need to remove the "mag block shelf" from the AR10 upper to make them work

JP Enterprises also makes their own rifle. They don't sell any stripped receiver and most of it is proprietary.

DPMS and Armalite what possibly* works between the two

*Realize these rifles are close in dimension, the parts could be replaced but probably shouldn't be per the recommendations of DPMS and Armalite. They could work or they could not, due to tolerance stacking-best bet is to get the correct parts. There is not a standard between manfs like the AR15. There is no "mil spec" and each manf has their own tolerances/standards.

I personally think switching parts between the two is stupid.  It might work, but if you stick DPMS parts in a AR10, and trash your warranty, you might have a tough time convincing them to honor their lifetime warranty. I do believe the armalite parts are better, even though they might be more expensive. Don't put cheap crap in your rifle if you might have to depend on it.

FF tubes will not interchange due to the thread pitch differences between the two.

Bolt carriers groups are interchangeable as long as they headspace correctly.

Bolts might

Barrels are interchangeable, but cause problems due to a 3/16" length difference in gas tubes. Armalite uses the longer gas tubes to use standard AR15 handguards. the 3/16" makes up for the wider barrel nut/bigger receiver

Armalite "carbines" use a mid-length gas system while DPMS "carbines" use a carbine gas system. Rifle gas> Mid-length >carbine in terms of being better/smoother

Barrel nut threads are different so you have to buy the correct handguard system for the upper receiver you are using.

Pic stolen form Ar15 barrels

Armalite on a DPMS. It will work but you have a gap at the back

Link Posted: 5/18/2008 4:00:32 PM EST
[Last Edit: TaylorWSO] [#4]

25 Gen2, 20 gen1, 10 gen1 round mags

Link Posted: 5/18/2008 4:00:36 PM EST
[Last Edit: TaylorWSO] [#5]
Comparison of the Amalite rifles and the DPMS- This is not to meant to be a pissing match. Just a side by side comparison of the rifles. I was getting tired of the "AR10 cost too much" crowd. Just so you know what you're getting for the extra cash.

see update on specifics below, ar10s now have the forward assist

Armalite technical Spec Info can be found here
Link Posted: 5/18/2008 4:00:40 PM EST
[Last Edit: TaylorWSO] [#6]
AR10 vs SR25 Comparison

Note: The information that appears below is from the Armalite website.. The original can be found at http://www.armalite.com/library/tech_notes/tnote06.htm

October 19, 1999


The purpose of this technical summary is to answer repeated questions concerning ArmaLite AR-10B series rifles, with an emphasis on differences between the AR-10B series, the M-16 series service rifle, and the SR-25 rifle produced by Knight's Armament Company (KAC).

GENERAL:  ArmaLite's priorities during development of the AR-10 were technical excellence first, and interchangeability with the KAC SR-25 and the M-16 following.  Because of the small number of early AR-10s produced between the late 1950s and early 1960s, no effort was made to maintain interchangeability with them, and no testing has yet been conducted to determine which parts interchange.

The design of the SR-25 emphasized interchangeability with the M-16 considerably more than ArmaLite has with the AR-10.  While both approaches are sound, the difference in priority has resulted in a number of technical advantages in the ArmaLite AR10 design.

For brevity, the new ArmaLite rifles are collectively referred to as AR-10s.  Four models of the AR-10B series exist:

AR-10B:  The base model of the new ArmaLite line.  It is patterned after early 1960 era rifles, and is produced largely for nostalgic reasons.  The charging handle looks like an upside down trigger and is located at the front of the carrying handle.  It special brown furniture and a rear sight elevation window at the rear of the carry handle.

AR-10A2; virtually identical to the M16A2 service rifle, but caliber .308.

AR-l0A4:  A flexible combination of the AR-10A2 and the AR-10(T).  It is generally identical to the AR-10A2 except that the upper receiver and gas block are manufactured with the “Picatinny Rail” sight mounting surfaces of the AR-10(T).  Removable iron or telescopic sights are optional.

AR-10(T); target model featuring a 24 inch long, medium weight target barrel, tubular handguard, match trigger, and Picatinny Rail receiver and gas block.

Each rifle is matched by a similar carbine: virtually identical save for a 16 inch long barrel.  The T carbine is equipped with a standard trigger rather than the match trigger of the AR-10(T) rifle.

BUTTSTOCK:  M-16A2 type shell.  A rounded buttplate is used to reduce sharp, uncomfortable edges.  A thicker, nylon trap door is used provide protruding checkering for good grip.  ArmaLite's feature olive green furniture (stocks, grips, and handguards) as a standard feature. Black furniture is available as an option.

BUFFER:  Similar to that of the M16 rifle, but dimensioned for the AR-10.  It is of aluminum construction containing the same weights and buffer disks used in the M-16.  The KMC buffer is a simple turned nylon plug.  The purpose of the weights is to reduce elastic rebound of the carrier from the barrel extension.

OPERATING SPRING:  32 coil 17-7 stainless steel versus the KMC 40 coil spring.  The shorter spring reduces slamming of the bolt carrier against the barrel extension.  The ArmaLite buffer places a slight preload on the spring, reducing the need for the longer spring.  The ArmaLite spring and buffer are usable in the KMC SR25.

UPPER RECEIVER:  Three versions are built: the AR-l0A4 version topped off with a Picatinny Rail (Weaver style) sight mounting surface, the AR-l0A2 version bearing an integral carrying handle, and a slightly modified AR-10A2 version made for the trigger-style charging handle of the AR-10B. ArmaLite produces a removable front sight and removable carrying handle for use on the Picatinny Rail surfaces.

ArmaLite upper receivers are forged rather than extruded or cast, and include an integral case deflector.  ArmaLite’s uppers are available for the KMC Lower Receivers.  KMC use of an extrusion instead of a forging requires a flat-sided receiver form; the core of the ArmaLite upper receiver is generally cylindrical, and quite similar to that of the M-16.  No Forward Assist is provided.   It is not considered necessary given the more powerful operating spring used.

BARREL NUT:  Two barrel nuts are used on the ArmaLite rifles: a simple ring style on the target models, and a rather more complicated nut for the -A2 and -A4 models that adapts standard M16 handguards to the AR-10.

The relatively complex -A2 barrel nut was designed to allow a spring loaded slip ring to be used to hold standard rifle handguards. This system is preferable to the early jam nut style handguard ring used on 1960 era AR-10s and on current SR-25s because the jam nut system loosen rapidly as the barrel expands during firing.   ArmaLite abandoned jam nut type handguard rings early in the AR-15 program.

The AR-10(T) barrel nut is a ring that bears internal threads matching those of the upper receiver, and an external diameter matched to the bushing of the handguard.  Because of the need to raise the gas tube, the gas tube holes of the ArmaLite nut are .010 farther from the boreline than those of the KMC part, but they remain interchangeable.

CARRIER:  The AR-10B carrier is virtually identical to that of the SR-25.  It is externally phosphated instead of chrome plated as with the SR-25, but is chrome plated in the gas expansion chamber like the carrier of the M-16.  The carrier key surface is .010 inch farther from the boreline than that of the KMC carrier, and .030 further to the rear for better gas transfer into the carrier.   Like the KMC carrier, the ArmaLite carrier will not allow a standard width hammer to enter the ArmaLite Carrier Assembly.  Initial testing has shown that the carrier and bolt group is interchangeable with the KMC components.

FIRING PIN:  Similar to the KMC firing pin, but with several key improvements.  The firing pin tip bears a short cylindrical surface just behind the tip.  This allows the bolt to have a cylindrical section just behind the bolt face, reducing the possibility of sheared primer material jamming into the opening.  The KMC firing Pin and Bolt have tapered surfaces at this point.

The ArmaLite firing pin has a single flange, and a cylindrical section before it that mounts a firing pin spring.  The firing pin spring greatly reduces the light firing pin strike produced in M-16 type rifles when the bolt locks, and thus reduces the possibility of slam fire.  In addition, it positively prevents incorrect assembly of the bolt carrier assembly.  The KMC firing pin has two flanges which makes it possible to install the firing pin retainer in front of the second flange: the carrier assembly appears correctly assembled but the firing pin cannot strike the primer.

BOLT:  The Bolt is similar to that of the KMC model.  Like the KMC bolt, it bears tapered lugs with increased root width for added strength. Six locking and one Safety Lug (patent pending) are used.  This system provides greater strength than the seven conventional locking lugs of M16 type bolts.   The firing pin hole has been reduced in diameter to prevent primer material from extruding into the firing pin hole if cartridge pressures are high or if primer material is soft.

GAS RING:  A single three-turn McFarland gas ring is employed rather than the three piston rings of the early AR-10s and the SR-25.   This construction cannot suffer reduced gas energy due to alignment of the splits of the conventional rings.  The McFarland ring functions perfectly on the SR-25 bolt.

EXTRACTOR:  The extractor is patterned after that of the prototype ArmaLite AR-16 rifle.  It doesn’t interchange with either early AR-10 or SR-25 extractors.

EJECTION PORT COVER:  Generally identical to that of the M-16, but a half-inch longer to accommodate the 7.62mm cartridge.

EJECTION PORT COVER SPRING:  Due to the close fit of the ejection port cover to the upper receiver, insufficient space was available to accept a standard M-16 ejection port cover spring.  In addition, the wider ejection port would result in the short leg of the standard spring protruding into the ejection port, and could injure the fingers of a firer hand loading or clearing a cartridge or case.  A special spring was designed which fit the existing reinforcement ribs of the ejection port cover to solve the clearance problem, and with a shorter leg to prevent injury to the shooter.

GAS BLOCK:  Steel, bearing a short segment of Picatinny Rail mounting surface for sights or other accessories.  It may be loosened to zero the removable sights.  It is one, cross-slot longer than the KMC gas block to allow more secure attachment of hardware.

GAS TUBE:  .240 Longer than the M-16 gas tube used by KMC to allow use of standard handguards and the spring loaded slip ring of the AR-10A2 and -A4 (see above).

BARREL:  The AR-10(T) barrel is produced from a match grade, stainless steel barrel blank.  The standard AR-lOA2 and -A4 barrels are button rifled and chrome lined, with stainless barrels available as an option.   Target barrels are 24 inches long; standard barrels are 20 inches long.   Carbine length barrels are 16 inches long.  Replacement of the barrel requires special tools, and should be performed only by ArmaLite personnel or a qualified gunsmith.

RECOIL CHECK:  The AR-lOA2, A4, B, and all carbines, bear a three slot recoil check on the muzzle.  The recoil check is threaded and pinned into place, and the end of the pin is welded to the check to prevent its removal.

HANDGUARD:  The AR-10(T) employs a tubular fiberglass handguard assembly.  The A2 and A4 versions accept either M16Al or M16A2 style handguards.

The AR-10(T) handguard is constructed differently from the KMC version.  The handguard-locating stud is pressed into a recess in the handguard bushing rather than riveted to the tube through the bushing. Instead of a bare fiberglass end, the ArmaLite handguard terminates in an aluminum sleeve that protects the fiberglass, reinforces it, and provides a mounting point for the sling swivel.

LOWER RECEIVER:  The AR-10 lower receiver follows the familiar lines of the M16 much more than that of the SR-25.  The longer ArmaLite magazine catch button need not be mounted in a depression in the side of the receiver as is the M16 button used in the SR-25.  The AR-10B button can be operated without removing the hand from the grip.  The familiar fence protecting the M-16 magazine catch from accidental actuation has been built into the AR-10B.

The AR-10B series Lower Receiver is not interchangeable with either the SR-25 receiver or those of the first generation AR-10 or AR-10A. ArmaLite Lower Receivers are NEVER sold separately.  All ArmaLite rifles are factory built.

TRIGGER MECHANISM: The AR-10(T) employs the ArmaLite two-stage match trigger as standard.  The B, 'A2, and 'A4 models employ the single stage trigger assemblies, but may be fitted with the two stage trigger mechanism as an option.

BOLT CATCH:  The SR-25 employs the M-16 bolt catch.  This device was designed to stop the small M-16 bolt carrier assembly, not heavier AR-10 bolt carrier assembly.  The AR-10 bolt catch is larger and stronger than that of the M-16/SR-25 to function with the heavier AR-10 components. It is designed to automatically catch the bolt when pressed upward by the bolt catch trip in the follower.

MAGAZINE CATCH BUTTON:  Identical to that of the M-16, except that it is somewhat longer to allow it to protrude from the side of the wide AR-10 lower receiver.

MAGAZINE CATCH:  An improved, machined catch with a longer engaging surface to capture the magazine better, elimination of a bevel to prevent excess upward movement of the magazine, and a longer shaft to span the wider receiver.

MAGAZINE:  The AR-10 magazine is based on the magazine of the M14 Rifle.  The M-14 magazine is well proven and available in large numbers.  It is both stronger and more reliable than that of early AR-10 and similar magazines.  It is made in 10 round capacity.

The AR-10B magazine does not bear a latch plate on the rear surface like that of the M-14 magazine.  The lower receiver, however, has a clearance cut up the back of the magazine well to allow insertion of an M-14 magazine.  A 20 round M-14 magazine can therefore be modified to function perfectly in the AR-10.  This modification requires changes to the feed lips cutting a magazine catch opening cutting a slot down the back of the magazine replacement of the follower with a new follower addition of a bolt catch trip and spring a slight change in the follower spring.

The most unique aspect of the ArmaLite magazine is the follower.   A top surface similar to that of the M16 magazine has been combined with a form suited to the M-14 magazine box.  A patented spring-loaded plunger has been installed in the follower.  When the follower rises to the top of the magazine box, this plunger pops into the track at the rear of the magazine well and trips the bolt catch, thus holding the bolt carrier assembly to the rear.

The magazine will continue to function in the M-14 rifle, but will not trip the M-14 bolt catch unless the AR-10 follower is replaced with the M-14 follower.   The latch plate at the rear of the magazine (which engages the M-14 magazine catch) may be sufficiently weakened by removal of its upper half that it breaks off, rendering the magazine usable only in the AR-10.

USING M-14 RIFLE MAGAZINES:  The AR-10B magazine is based on the proven M-14/MlA rifle magazine.  A good quality metal 20 round M-14/MlA magazine can be altered to work perfectly in the AR-10B. U.S. GI and imported Chinese magazines are acceptable.  Commercial metal magazines with blue finish or pressed latch plates require replacement of the shell.  Fiberglass magazines (i.e. Thermold, etc.) are totally unsuitable for conversion.

ArmaLite sells 20 round magazines when available.  ArmaLite will provide converted magazines for a fee or on a 2-for-1-exchange basis. Magazine conversion kits allow a customer to convert all metal M14/M1A magazines and metric FAL magazines to AR-10B series magazines.

MAGAZINE INTERCHANGEABILITY:  10 round AR-10B magazines and converted 20 round M-14 magazines will not work in early AR-10/AR-10A rifles, or in the current SR-25 rifle.  Magazines for those rifles will not work in the new AR-10B series rifles.  Unless converted with the reversible magazine conversion kit, M-14/M1A magazines should not be used in the M-14 or M1A after modification.
Link Posted: 5/18/2008 4:00:44 PM EST
[Last Edit: TaylorWSO] [#7]
AR10 bolt compared to AR15

courtesy ar15barrels

PRS on ar15 and AR10, pic angle is oblique not making the difference stand out as well as i would like.

Link Posted: 5/18/2008 4:00:48 PM EST
[Last Edit: TaylorWSO] [#8]

Which zero? Assumption: 2.5" sight height, 20" Barrel AR10 2700'/sec 147 FMJ Zero's in
Range of Zero (Yards)
100 -note you don't get a "double zero"
218/42 (200m zero)
316/27 (25m zero)
654/11 (600m zero)
Range of Zero (Meters)
100-note you don't get a "double zero"
Looking at the differences between the 200 and 250 zero's you get the following higher POI for the 250 zero
200/45 vs. 250/35 yard zero difference
0= 0
50= +0.6
100= +1.3
150= +1.9
200= +2.6
250= +3.2
300= +3.8
350= +4.4
400= +5.1
450= +5.8
500= +6.4
550= +7
600= +7.7
650= +8.2
700= +9
750= +9.6
800= +10.2
850= +10.9
900= +11.4
950= +12.1
1000= +12.7
I zero at 45 to get the 200 zero and to get a "double zero" plus a decent capability at 300
200/45 yard zero
Range(yds) Drop(in)
Hornady 168 TAP vs. 168 superperformance
Gun first

Cheap parts AR10, cost about 800 bucks with everything bought on sale. 18" chrome moly eagle arms barrel cut down from 20" with a rifle gas system, SWS rail, 552 EoT (not shown), with krylon. Mags were gen 1 AND Gen 2.
The rounds were the 168 gr TAP with the nickle cases and the new 165 Gr SST loads.

Note COL was a little shorter for the SST 2.74" vesus TAP 2.801, looks like the same primer non crimped. The bullets were also not crimped.

Pulled rounds, 168 AMAX OTS, Pulled TAP and then the SST with cannelure and shorter bullet. You cnat really tell but the base of the bullet for the SST is different than that AMAX
168 AMAX 167.4 grns
168 TAP 168.0 grns
SST 165.1 grns
SST powder, ball mix with all about the same avg size. Sorry its a fuzzy pic 48.4 grs

TAP powder, stick that looks exactly like varget to me. 44gr

Impressions: One the SST bullet is not built for accuracy. The group was nearly twice the size of the TAP. I was really looking forward to seeing a 168 or even 178 AMAX in the SP load. This gun loves the 168 AMAX. I know they stress the extra velocity, but I need a better bullet to use that velocity downrange. Not impressed with the bullet.
18" AR10, 60 degrees, wind neg 3200' msl
168 TAP= 2514AVG (13.7SD)
168 SST= 2632.5AVG (13.15SD)
Thats 118fps better in a 18 in barrel, no sings of pressure, very slight/more recoil. My 18" has a rifle gas tube, many people report bad pressure signs with carbine length gas tubes (dpms)
Other threads
Usually FMJ surplus usually does right around 2600 for me in 18" barrels with a 16" around 2550's or so

Randall had this which I stole, which is great for comparing velocities barrel length.

Using something like 155gr TAP/AMAX, will the 22" M1a do anything the 18" AR won't"
View Quote

You loose around 150-200fps. Out to approximately 400 yards, the 18" rifles work as well;beyond that, the longer 22" barrels start to offer some advantage.FWIW, I prefer the 18" barrels––after switching to AR15's for Hi-Power,I sold all my personally owned 22" barrel M1A's, except for one doublelugged, bedded, scoped precision rifle.
View Quote

Velocities 16” AR10 (multiple sources posted in this forum)

Federal Gold Metal Match, 168gr: 2470 fps
Win 150 grain, Balistic Silvertip = 2598
Hornady 155 TAP= 2513
South African 147 FMJ=2508
Portugese 146 FMJ= 2547
Aussie 144 grain= 2601
Argentine 144 FMJ= 2501
45.6 gr Varget 155 Amax=2596
Following Velocities 18” AR10 3200’ MSL 60-80*F

Superperformance 168 SST= 2632AVG (13.15SD)
168 Hornady TAP=2514AVG (13.7SD)
Silver bear’09 147gr= 2640avg (26 SD)
FN-70 150gr AP=2606AVG (18SD)
FNB 81 147gr=2594AVG (32 SD)
DAG 147gr=2549AVG (13SD)
PPU 09 147gr=2602AVG (18SD)
LC ‘02 147 gr=2633AVG (16 SD)
WCC(ROK) ‘09 147gr=2659AVG (14.5SD)
PMC ‘07147 gr=2557AVG (47SD)
LC brass 147gr 45gr varget= 2540AVG (no SD)
155grAMAX in FN-70 brass =2606AVG(18SD)
175 SMK/44gr VARGET, WIN BRASS 2459AVG (no SD)
Velocities 20” (multiple sources posted in this forum)

Australian 147gr= 2775 fps
Federal 168gr GMM= 2600 fps
Mk118LR= 2559
45.6 gr Varget 155 Amax=2717
Win 150 grain, Balistic Silvertip = 2729
Hornady 155 TAP= 2625
South African 147 FMJ=2660
Portugese 146 FMJ= 2636
Aussie 144 grain= 2709
Argentine 144 FMJ= 2610
Three barrel lengthes and velocities with SB 147 gr (same day)70 degrees, no wind 3200 msl
16" CL barrel/ML gas 2605 avg (21 sd)
18" CM barrel/rifle gas 2629avg +24(30 sd)
20" nm ss barrel 2673avg +44, +68 (26 sd)
2" added, 24fps, 4" added 68 fps. Nearly double the jump from 18" to 20" (44fps) versus 16" to 18"= (24fps)
AR15 vs AR10 drops (M855 vs win M80) 100 yrd zero 16" and 20" barrles 2.5" sight height

         ar15                 ar10
      16       20"       16"       20"

100  1.9      2.0       1.6       1.6
200  1.4      2.1        .2        .2
300  -5       -3         -9        -9
400  -20     -16       -24       -26
500  -44     -37       -49       -52
600  -81     -70       -87       -92
700  -136   -119     -138      -145
800  -214   -187     -207      -217
TA11E Acog
The BDC is made for 175 gr ammo at 2651 fps (22" barrel).
100 meter ZERO is tip of Chevron

2.2 moa to inside tip of Chevron, 200 m

4.7 moa to tip of BDC, 300 m

8.3 to 400 m

12.4 to 500 m

17.0 to 600 m

22.3 to 700 m

28.4 to 800 m
To shoot 147gr from a 16" barrel to need to zero the acog at 45 yards to get the following difference. Good for GP out to 500yards, after that it starts to fall off.

range    BDC        147gr/2250          difference

0              -2.5        -2.5                        0

50          -0.6        0.2                        -0.8

100         0              1.5                          -1.5

150         -0.8        1.1                        -1.9

200        -3.2        -1                          -2.2

250        -7.2        -5                            -2.2

300        -13          -11.1                      -1.9

350         -20.7     -19.6                      -1.1

400         -30.5      -30.7                    0.2

450        -42.5      -44.6                      2.1

500        -57          -61.8                      4.8

550        -74.1      -82.5                      8.4

600         -94.1      -107.1                  13

650        -117.2   -136.2                    19

700         -143.8    -170                      26.2

750        -174.1    -209.3                    35.2

800         -208.5   -254.4                    45.9

850        -247.3    -306                      58.7

900        -291      -364.5                  73.5

950        -339.9    -430.5                    90.6

1000       -394.5    -504.6                  110.1



Link Posted: 5/18/2008 4:00:53 PM EST
[Last Edit: TaylorWSO] [#9]
Help, my rifle is short stroking/FTE/FTF- whats wrong?????

You need to tell us the following before we help you

Model/year built: this will tell us what upgrades you have
Ammo used: hopefully more than 1 type and at least one decent brand
Lube type-application: clean/lube before shooting?
Mags used: Gen 1 or Gen 2/10, 20, or 25 round? Did you try more than 1?
Extractor setup: double springs/ Orings/single spring/insert/
And then describe it, its not a "jam"- those are strawberry and grape at my house

Bolt over base? stubbed round? three point bind? failure to eject? Ripped case rim? Double feed


It could be a multitude of things

What to check

Single shot bolt holdback working? Load a single round in the mag, chamber and fire. Does the bolt lock back? Does the bolt lock back on the bolt face or on the bolt carrier?

Is the gas block secure? Does it move freely? Are the screws tight?

Did you recently replace the FF tube?
Did you space/ correctly install the gas block? Spacing=make sure the space for the handguard cap is present if you replaced the original forearm with a FF rail.

Make sure that the gas tube is installed correctly and that the roll pin is present. check the rear of the gas tube to make sure it is not worn down and compare its outside diameter to that of the carrier key ID.

Hows the carrier and gas rings? Loose? see leaking gas/carbon? Did you build the upper and use a AR15 gas tube?

Hows the tension on the extractor? Will it hold a round? Does it take a lot of pressure to move it. It should be relatively stiff. If you took it apart to clean it, did you assemble the springs correctly add or lose the Oring?

How about the ejector?
Does it move freely? make sure there is not brass binding in the hole- a problem with softer fed brass. If you load a round and manually eject it, does it fling it out the side or does it just fall out of the chamber.  Check your EJECTOR and spring to see if you have proper tension and no brass shavings stuck in the ejector hole. If you're getting proper extraction (out of the chamber) and the base of the case is free of the bolt face (but not kicking the empty overboard) your ejector spring may not be pushing the case out through the ejection port before it's getting caught on the bolt's forward thrust while stripping a new round from the magazine (especially since you say you have no extractor issues and you are running a heavy buffer). This could also lead to the inevitable empty stuck above the bolt and jamming the charging handle forward (requiring removal of the upper to pull the empty out of between the charging handle and barrel extension).

Do you have the correct buffer tube/ buffer. Can you pull back the bolt far enough to engaged the bolt (not the BCG) on the bolt hold back catch. What type of buffer and spring are you running?

Does the ejected round have any mars on the case, is there 2 scrape marks near the shoulder, is there and extractor marks on the rim?

Double Feed/ 2F

Defined as two live rounds trying to feed into the chamber at the same time. A live round feeding into the rear of a fired round is a FtEx. The magazine is at fault 99.9% of the time. The other .1% is caused by over function causing the bolt to strike the inside of the LRE hard enough to jar rounds from the magazine. This is often seen on rifles with over large gas ports and weak buffer springs with light buffers.
Link Posted: 5/18/2008 4:00:57 PM EST
[Last Edit: TaylorWSO] [#10]
Terminal effectiveness

I stole this from here also here

good bullet selection here

Disclaimer-I'm no expert but I gathered info from reading and that's it. I don't shoot people for a living but I listen to those that do. You should to, Im basically repeating some info here in the FAQ


There are a lot of misconceptions about defensive ammo, penetration in the human and through barriers. While the 7.62 caliber weapon offers more in terms of penetration through barriers, it is really lacking in terminal effectiveness in the human body with some FMJ rounds. Since surplus has FMJ bullets, there are very few bullets that perform well on humans. Bigger is not always better. To get rid of humans you need incapacitation from a good shot, again shot placement being the most important factor. If you can hit all the time with perfect shots then FMJ will do just fine, but I like to cheat as much as possible when dealing with death so I will take any advantage I can get. So if you have the shot placement down then you need a bullet that will fragment on impact, but still reach a minimum depth of 12 to make sure you can turn the inner-human into goo and stop him. These parameters has been proven to work the best on people. Animals are a different story.

So wee need a bullet that will penetrate and fragment.

I stole this info from Doc Roberts, he is the expert.


03-27-10, 16:05

7.62x51mm is a lot of things, but aging it is not. If I knew for certain I was going to be in harms way on a given day and had the luxury of preparing for the encounter in a relatively static position, I would much rather be shooting a .308 with good ammunition than 5.45x39 mm, 5.56 mm, 6.5 mm, 6.8 mm, or 7.62x39 mm, as the .308 has the greatest likelihood of rapidly incapacitating an opponent over a wide variety of circumstances and potential engagement scenarios, as well as being much better at penetrating intermediate barriers and shooting into vehicles than the common assault rifle calibers. In fact, .308 is probably the best general purpose cartridge available; if I was limited to one rifle caliber, then .308 would be it, as it capable of shooting from up close all the way out to 1000 depending upon equipment and shooter limitations. It can handle all game in the lower 48 states with wise load selection, as it works with projectiles from 110 gr to 180 gr––fragmenting, barrier blind, as well as good hunting and match loads. The only downside is the additional weapon and ammo weight, bulk, and cost compared to assault rifle calibers.Steel jacket M80 FMJ fragments down to 2800 f/s, at which point it begins to perform just like M80 copper jacket FMJ

M118LR offers very inconsistent terminal performance––sometimes fragmenting but other times penetrating deeply before yawing without fragmentation. In addition,

M118LR tends to have poor performance against intermediate barriers, especially auto windshields

At this time the Hornady 155 TAP offers outstanding accuracy nearly on par with SMK’s, as well as more consistent terminal performance, better incapacitation potential and superior performance through glass intermediate barriers than SMK’s; as a result, the Hornady 155 gr TAP using the polymer tip AMAX bullet is the probably best general purpose choice for LE snipers. BH also loads AMAX bullets. The Nosler 150 gr Ballistic Tip PT, Hornady and Nosler 155 gr OTM, Federal 165 gr TRU JHP, Sierra Game Kings, and Weapons Unlimited Hostage Rescue JHP also work well.

The 155 gr AMAX consistently offers nearly perfect terminal performance characteristics––ideal penetration, good fragmentation, and perfectly placed large temporary cavity. All of the .308 AMAX bullets we are aware of fired in OIS incidents to date have remained in the suspects' torsos; damage on autopsy has been quite impressive and exactly as predicted based on lab analysis. The 110 gr AMAX has a shallower penetration depth with a rounded temporary stretch cavity, while the 168 gr and 178 gr AMAX have deeper penetration than the 155 AMAX, with a more oval, narrower temporary stretch cavity. BH also loads AMAX bullets.
As noted in previous threads, the JSWB-IPT discovered that Lake City has manufactured TWO distinct types of M80 FMJ over the last several decades, one using a thick copper jacket that does not fragment, as tested by Dr. Fackler at LAIR and another previously untested version using a steel jacket that fragments at velocities above approximately 2800 f/s . Yaw and fragmentation occurs at about the same penetration depth as with copper jacket M80, and is thus deeper than ideal (ie. NL too deep). When the velocity drops to below 2800 f/s (by approx 100 m from 22" barrel M14), M80 steel jacketed bullets no longer fragment and instead act like the non-fragmenting copper jacketed M80 FMJ.
From the 6.8 PDF: However ammunition with terminal performance far SUPERIOR to currently issued M80 ball is MANDATORY to optimize the potential of 7.62 mm

rifles for CQB and urban combat. Neither type of current 7.62 mm M80 FMJ possesses ideal accuracy or terminal performance characteristics, especially from barrels shorter than 16-18”. 7.62 mm M118LR 175 gr OTM used in sniper rifles like the Mk11, M110, M24, and M40A3 is very accurate and offers good performance at longer ranges––making it ideal for sniper use. However, the documented inconsistent close range terminal performance and poor intermediate barrier performance of the heavy SMK OTM make it a less than ideal choice for CQB engagements, urban combat, and short barrel use. Improved ammunition is required to optimize terminal performance with shorter barrel 7.62 x 51 mm weapons (Mk14/M14 EBR, KAC SR25K, HK417, FN Mk17 SCAR-H).

So what ammo does what

some detail (not my pics)

And just because this is awesome

Link Posted: 5/18/2008 4:01:02 PM EST
[Last Edit: TaylorWSO] [#11]

paralax adjustement, anyone knows how to adjust scope


The author is a man named Paul Coburn and his job is
evaluating optics for a living. He is highly regarded in the field and
does testing for some major companies. So no if's, and's or but's
regardless of if you agree or disagree with the writting style he is
giving the straight poop on the subject. Here it goes...

Thread link: http://www.benchrest.com/forums/showthread.php?t=15138

answered questions about scope parallax about 300 times, and it's
always a long drawn out thing, going several e-mails, and a few phone
calls. It doesn't seem to make any difference how long the guy has been
shooting, this one always keep screwing guys up.

OK... here goes (Whew, this is gonna be a long one).

There are several things that go on inside a scope, and in the eyes at the same time. Some of them workie against each other.

some terminology first... and we'll leave out lenses that are there to
correct some optical or color errors, but don't have anything to do with
image forming.

We'll start at the front of it all, and work back.

1 - The "Object"... the thing that you are looking (shooting) at.

- The "Objective". The front lens is called the "Objective"... it forms
the first image of the "object" we are looking at (that why they call
it the Objective

It is the lens that "captures" all the light, that
is solely responsible for the image quality of the scope... if it is
poor, you can't fix the poor image later.

This lens is usually made
of two different types of glasses (called "elements") sandwiched
together, and is called an "Achromat".

The Achromat is fully color
corrected for blue and green. The red wavelengths are partially
corrected, but have what is called "residual color errors".

This is
the normal type of objective used in shooting and spotting scopes. In
quality, they can vary from badd, through sorta OK, to pretty damn good.

If one of the elements is made of an "ED" glass, or a "Fluorite"
(CaF) glass, the two element lens can be very good to friggin'

In some instances, objective lenses are made of three
elements, and all three colors (blue, green, and red) are completely
corrected. This type of lens is called an "Apochromat", and this is the
finest lens that can be bought. The best of these can also have "ED"
glass, or Fluorite as one of the elements.

3 - The "First image
plane". The Objective focuses the light to make an image of the subject,
just like a camera lens. This image is upside down, and right/left
reversed. This is the first image plane, but NOT the "First image plane"
that is talked about when shooters talk about reticles.

4 - The
"Erector lens"... (if it is a group of lenses, it is called the "Erector
cell"). Because the first image is upside down/wrong way around, we (as
shooters) can't use it... so we flip it around with a simple optical
group called the "erector cell". This cell gives us a new image that is
right way around, called the second image plane. Moving this cell causes
this second image plane to move... so micrometer spindles are put
against the cell, to get elevation and windage adjustments.

5 - The
"Second image plane". This is the second real image plane in the scope,
and this is the image plane that shooters call the "First image plane"
when talking about reticles. In a fixed power scope, or in a variable
with a "First image plane reticle", the reticle would be placed in this
image plane.

This is where Premier Reticle puts those magical "Gen II" reticles.

- The "Zoom group". In a variable scope with standard (non-magnifying)
reticle, the zoom group of optics would follow #5. This group of lenses
can change the size of the image plane in #5 and then form a new (third)
image plane behind it.

7 - The "Third image plane" In variable
power scopes, this is the plane that the reticle is placed in. By being
here, it allows the image to change sizes, but the reticle to stay the
same size. In the context of reticles, this is the image plane that is
referred to as the "second image plane"

8 - The "Eyepiece". This
optical group is like a jewelers loupe. Is is (or should be) a super
fine magnifier. It's only job in the whole world, is to focus on the

Let me repeat that for those that live in Rio Linda...


CANNOT adjust, or compensate for, or do anything else when things look
bad in the scope, or when you can't hit the target... and you CANNOT use
the eyepiece to try to correct for parallax. That is sheer folly at
best, and raw stupidity at worst.

If you expect it to do anything
else, then stop wasting your time with long-range shooting, cuz you are
never gonna make it past mediocre... and take up golf!!

OK... now
that you know what the insides are like... lets move on. We'll use the
zoom scope for our examples. cuz if you can understand the zoom scope,
then the fixed scope is a walk in the park.

In the scope that is set
for infinity range, the object forms an image behind the objective (the
first image plane)... the erector cell "sees" that image, and flips it
over and makes it right way around in a NEW image plane (the Second
image plane). The zoom group adjusts the size of this image plane, and
makes a NEW image plane (the Third image plane) that is the desired
size. There is a reticle placed in this last image plane, and the
eyepiece focuses on the reticle AND the image at the same time.

When things are good, that's how the scope workie!


now the booger falls into the soup... IF the third image plane and the
reticle are not exactly, (and I mean EX-ACT-LY) in the same place, then
your eye cannot see them LOCKED together as one picture.

It sees
them as two separate pictures, and the eye will look at each separately,
and the eye can also look AROUND one to see the other.


are measured in metrics (aka Millimeters). Not because the Europeans
wanted the metric system 20 years ago, but because optical strings and
chains of lenses (like scopes) are really a string of numbers.

are constant ratios of "this divided by that's" that give image sizes,
"F-ratios", and image locations. It's so damn easy to do the engineering
using a 10 based system that the optical guys were using the metric
system way back in the 1800's.

The objective has a "Focal length"...
this is the distance behind the lens that the first image plane falls
when making an image if a subject that is at infinity (or very damn far

If the objective has a focal length of 100mm, then the image of that 1000 yd target is 100mm behind the lense.

the problem with geometric optics (which is what we are dealing with
here), is that they follow the laws of geometry... and optics make
triangles like rabbits make babies.

AND... in an optical chain, when
you change one thing, one angle, one ANYTHING, everything else follows
along and changes BASED on the ratios involved at THAT stage.

If we
take that same target, and move it to 100 yds, the image in the scope
moves BACKWARDS, going further into the scope. Not by much, but it
doesn't take much, cuz we're dealing with very small distances inside
the scope, and very high magnifications.

How far the image moves
back, and what it's new position is, is predictable by the mathematical
ratios of the angles formed by the subject and the first image... OR
(for us dummies that lost our slip sticks) by the ratio of the distances
to the Target and the focal length, multiplied by the focal length.
then ADDED to the focal length.

The target is at 100 yds (91440mm),
the focal length of the objective is 100, so the displacement is 1/914 x
100, which means that the first image is now at ~100.1mm. Hmmm only
.1mm, that doesn't seem like much.

Read the following paragraph twice...

a 1x scope, 0.1mm would mean nothing... but this displacement is
repeated throughout the chain, AND if any of the optical groups change
the image ratio (aka image size), then the displacement (aka ERROR) is
changed in direct proportion to the increase in magnification. So in a
3x scope, it would be .3mm, and in a 10x scope, it would be 1mm, and in a
30 power scope, the image would be 3mm behind the reticle.

Now, you should have seen a pattern in this last paragraph.


the same error in the objective (scope focused at 1000, and target at
100), the parallax INCREASES WITH MAGNIFICATION... got it?


now, if we do the same math for closer distances, like 50 yds, and 25
yds we will see that the error gets really big, so that with a target at
50 yards, and the scope set at 35 or 65 yds, the parallax makes the
combination un-usable.


Parallax is... when the image of the
target, and the reticle, are NOT in exactly the same plane, and by
moving the eye up and down... or side to side, either the target OR the
reticle appears to move in relation to the other.

You might see the
target move and the reticle stay still, or you might see the target stay
still and the reticle move over it... both are exactly the same, and
which you see, is only a matter of your OWN perception.

It is NOT possible to have parallax while moving up and down, but not have it when you are moving side to side.

If you think that is what you have, you have other problems... either you are moving the rifle, or you have eye problems.



This is the only way to do it...

First, screw the eyepiece out (CCW) all the way, until it stops.

If you wear glasses, put them on.

Hold the scope up and look OVER the scope at the sky, and relax your eyes. Then move the scope in front of your eye.

The reticle should look fuzzy

the eyepiece in 1/2 turn, and do the same thing again. You will have to
do for a while before the reticle starts to look better. When you start
getting close, then turn the eyepiece 1/4 turn each time.

Do this until the reticle is fully sharp and fully BLACK immediately when you look through the scope.

Than back off one turn and do it again to make sure you are in the same place.

Then LOCK the ring on the eyepiece, and leave it alone forever!


Set the scope down on something sold, where it can see something at a long distance... half a mile of longer is good.

can be on the rifle, and rested in sand bags at the range... but pick
something at least 1000 yds away... even further if possible.

If the
scope has an "AO" Adjustable objective, then set it for infinity, and
look at the distant object, and move your head from one side to the
other, or up and down if you prefer.

If the reticle seems to move, there is parallax.

the distance setting and try again... if you are very careful, you can
move your eye, and adjust the distance at the same time, seeing which
direction gets better.

With front objective adjustments, you can
turn them either way without worry... BUT with side adjustment scopes,
like the MK4-M3, the M3-LR, or the other LR family of scopes, the
adjustment must ALWAYS be made from the infinity end of the dial. Turn
the adjustment all the way until it stops (past infinity), and then
start turning it in a little at a time, until there is no parallax. If
you "overshoot" the proper setting, you can't just turn back a little,
you must go back to stop at the end of the dial, and start over again.

"AO"s dials are locked in place, and if the indicated distance doesn't
match the real distance, there's nothing you can do about it... the side
focus dials are not locked in place.

Once you have found the
setting for infinity on the side focus models, then (CAREFULLY) loosen
the screws, and set the dial so that little sideways infinity symbol is
lined up with the hash mark, so it is calibrated. You can also make
little marks or put on a paper tape for other ranges instead of using
the round dots that don't match any range.

Now you can set it to
infinity, but remember that you MUST turn the dial all the way past
infinity to the stop, EVERY TIME before going from a close range to a
longer range.

If you are set for 500 yds, you can go directly to 100
yds, but if you are set for 100 and want to set it to 500, you MUST go
all the way back to the stop, and then go to 500

This is because
there is a fair amount of backlash (aka SLOP) in this wheel linkage to
the focusing cell, so you can set it only from one direction to make
sure the slop is always on one side. The other problem with it is, even
if you decided that you wanted to calibrate from the other end... the
recoil will push the cell back. SO you must ALWAYS set these dials from
the infinity end of their scales.

To make it easy to not have to
remember... I always start from the end stop, when I change range, no
matter which direction I'm going in... it adds about 0.023 seconds!


Now... you gots a friend that says to set up a scope a different way???... he don't know doodly-squat about scopes.

The guy at the range said to do it a different way... he don't know either.

You know some guy who's in the Marines says to use your eyepiece to correct parallax... he doesn't know about optics either.

You got a friend that shoots benchrest and says something different... he don't know crapola!

This is the way, the only way, there is no other way.

... as Rushbo would say... this is from GOD-da .

You gots questions, just e-mail me.

You wanna "debate it", then go play golf, cuz you're wasting my time!

'lito (gettin' grumpy in my old age!)

Link Posted: 5/18/2008 4:01:06 PM EST

Originally Posted By TaylorWSO:
space held
Link Posted: 5/18/2008 4:01:10 PM EST

Originally Posted By TaylorWSO:
space held
Link Posted: 5/18/2008 4:01:13 PM EST

Originally Posted By TaylorWSO:
space held
Link Posted: 5/18/2008 5:38:07 PM EST
For what?
Link Posted: 5/18/2008 10:39:21 PM EST
What the heck are you doing?
Link Posted: 5/18/2008 10:48:23 PM EST
Im trying to get a FAQ post created and a information section with everything together.
Link Posted: 5/19/2008 12:03:09 AM EST
Link Posted: 5/19/2008 9:15:56 PM EST
My only complaint is that you keep referring to it as a .308 rifle when it is a 7.62x51 NATO rifle.

Also, in addition to what you posted:

The reason is because Armalite has spent a lot of money producing the AR-10 when no-one else would. They have spent a lot of money building the name and reputation not to just have someone else use it to describe their rifle, Yes its a big deal. See trademark tacked topic

I, and many others, get tired of hearing how AR10s break bolts and other miscellaneous bullshit complaints that are, in reality, complaints about other 7.62/.308 ARs.  That's where, other than bubba mags, most of the complaints about "AR10s" come from, non-AR10s.

Link Posted: 5/19/2008 9:33:56 PM EST

Originally Posted By LARRYG:
My only complaint is that you keep referring to it as a .308 rifle when it is a 7.62x51 NATO rifle.

Its easier to type 308 vs 7.62x51 NATO
Link Posted: 5/24/2008 6:43:14 PM EST

Thank you for making the effort to pull all of this information together.  It is very helpful and greatly appreciated.  I'm patiently waiting for my GAP-built AR-10s and can't wait to join the club.


Link Posted: 6/4/2008 10:48:03 PM EST
Very Informative. Thank you.
Link Posted: 6/28/2008 1:17:30 AM EST
Link Posted: 7/11/2008 1:47:51 PM EST
How about a list of stocking dealers and distributors for the AR10.......?? Since some of us cant seem to find one in stock anywhere....

Link Posted: 7/11/2008 5:07:55 PM EST

Originally Posted By ARmory04:
How about a list of stocking dealers and distributors for the AR10.......?? Since some of us cant seem to find one in stock anywhere....

FAQ #10 has the ones I know of
Link Posted: 9/1/2008 5:42:58 PM EST
[Last Edit: Duffy] [#26]
So an SR25 upper isn't compatible with an AR10 lower?  The FAQ says no, see pics below but there are no pics or other information.  I read an AR10 upper can work on an SR25 lower, so why not the other way around?
Link Posted: 9/1/2008 5:49:58 PM EST
[Last Edit: TaylorWSO] [#27]
Originally Posted By Duffy:
So an SR25 upper isn't compatible with an AR10 lower?  The FAQ says no, see pics below but there are no pics or other information.  I read an AR10 upper can work on an SR25 lower, so why not the other way around?

This is from the tech bulletin no 6, on the 1st page near the bottom.

"The AR-10B series Lower Receiver is not interchangeable with either the SR-25 receiver or those of the first generation AR-10 or AR-10A. ArmaLite Lower Receivers are NEVER sold separately. All ArmaLite rifles are factory built."

its old as you can tell, because you can buy armalite receivers now.

If you have pics, post them please, as I don't have a sr25

ETA the takedown pins are larger in the sr-25 .28ish  vs the ar10 .275"
Link Posted: 9/1/2008 5:59:29 PM EST
[Last Edit: Duffy] [#28]
Thanks for the speedy reply, yes I did read that.  It talks about the AR10B, the 10B isn't even compatible with other newer AR10 uppers I don't have an AR10B.  Come to think of it, I think it's probably an exercise in futility, I've never seen an SR25 upper for sale, SR25s all seem to be sold as complete rifles.  Also if I did find an SR25 upper, it'd probably cost twice as much as a comparable AR10 upper

I've never seen an SR25 upper fitted to an AR10 lower, probably for the reasons mentioned above.  Or it's just not compatible with an AR10 lower, no matter which version.

I did a search on "SR25 upper on AR10 lower", not too many usable results, except I did find this, an AR10 upper receiver for the SR25 rifle

Oh yeah, I'm sure you know about this site, I found lots of pics on biggerhammer.net

On their SR25 forum, I found a poster asking which lower will work with an SR25 upper, the answer from another poster:
Armalite AR10 uppers can be adapted to the SR25 lower. You have to enlarge the front upper hole to accomadate the bigger push pin on the front of the 25. You also have to make a depression in the left side upper for the bolt release and last remove the lower cartridge guides (2) on the insided of the AR10 upper so the magazine can be fully inserted. I did this to a AR10 carbine upper as KAC gave me a flat NO! to the question during my SR25M build.

The AR10 upper on armalite's site for sale to be used with an SR25 is slightly different than the normal AR10 upper it seems, it's modified for the SR25.
Link Posted: 9/1/2008 6:47:12 PM EST
[Last Edit: LARRYG] [#29]

Originally Posted By Duffy:
Thanks for the speedy reply, yes I did read that.  It talks about the AR10B, the 10B isn't even compatible with other newer AR10 uppers I don't have an AR10B.  Come to think of it, I think it's probably an exercise in futility, I've never seen an SR25 upper for sale, SR25s all seem to be sold as complete rifles.  Also if I did find an SR25 upper, it'd probably cost twice as much as a comparable AR10 upper

All of the current crop of AR10s are the AR10B series since they were introduced about 14 or so years ago.

The AR10B just also happens to be the model name of the retro model.
Link Posted: 9/1/2008 7:21:49 PM EST
Ah so, thanks, that makes sense now
Link Posted: 10/22/2008 6:28:22 AM EST
What's the cut-off date for Armalite's recommended tune-up package on AR-10s? I know I've seen it mentioned here or on Armalite's website before, but can't seem to find the info now that I need it. I may be purchasing a mint AR-10T tomorrow that was manufactured in 2006. Thanks in advance!

Link Posted: 10/22/2008 12:34:05 PM EST
I have no idea, I would call armalite and ask, or maybe post in the industry forum, Tim  can tell you there.
Link Posted: 10/23/2008 10:57:29 AM EST
Link Posted: 10/24/2008 11:51:31 PM EST
Link Posted: 10/25/2008 12:14:36 AM EST
Those are the only ones that work properly without any mods to works.
Link Posted: 11/23/2008 9:47:19 AM EST
[Last Edit: colt933] [#36]
I've built at least 100 AR15s but now am now interested in getting in to the AR10 because of the impending legislation (and of course I always wanted an AR10 but was too busy with other stuff).  I've recently purchased new Aero Precision SPR-2 and Noveske N6 lowers and have a few questions before I start buying parts:

1.  Who sells a wrench for the AR10 FF barrel nuts?  Armalite doesn't show one on their site but this FAQ states that you need a bigger wrench for these.

2.  DPMS now makes one of THESE.  Will it work with an Armalite upper?
Link Posted: 11/23/2008 3:43:04 PM EST
a standard AR wrench will work for the regular hand guards/delta ring/barrel nut. The bigger wrench is needed for the free float tubes like this

I would get the upper receiver blocks from armalite vs the "claw" from dpms. receiver blocks have more area for putting on barrels, vs just the pin holes on the claw

Link Posted: 12/3/2008 12:55:31 PM EST
Does anyone know if Knight's Armament makes a rail that will fit a DPMS LR-308 with the 24" stainless Bull barrel?
Link Posted: 1/2/2009 6:35:36 PM EST
Link Posted: 1/2/2009 7:28:40 PM EST
Originally Posted By Cold:
Should this stay here or go to AR Variants, what do people think?

I think THIS IS A GREAT IDEA, I think we need a tacked thread of this IN BOTH FORUMS.

Taylor, nice job buddy, I really mean it, this needed to happen.

I think we need a dedicated 308 AR Variant forum. There seems to be an awful lot of development in the 308 platform. I am quite sure that Armalite wants to retain their "own" forum since they are an industry sponsor.

If nothing more than a simple chart as to what components are the same among the variants and the ar15, magazine usage, etc.. I don't think we need to get into which one is better because that fight will go on longer than the ones in the middle east.

I think the common parts/interchangability chart would be the most helpful.

My $.01 (I'm anticipating a tax increase)


Link Posted: 1/2/2009 9:13:20 PM EST
Link Posted: 1/2/2009 10:04:47 PM EST
Originally Posted By Cold:
Post this suggestion in the "suggestions" forum, on this site. Goatboy et all are very receptive to this kind of thing, thats what this place is for, the end user, so I think a post there on your behalf on such a topic would be very well recieved.

I IM'd Goatboy. I couldn't find a suggestions forum. I don't know if it is the time of day night or just my plain stupidity.

Link Posted: 1/6/2009 6:45:50 PM EST
Originally Posted By Cold:
Post this suggestion in the "suggestions" forum, on this site. Goatboy et all are very receptive to this kind of thing, thats what this place is for, the end user, so I think a post there on your behalf on such a topic would be very well recieved.

I have and IM'd a few times No luck yet.

I dont think it NEEDS to be in the variants but the link in the tacked 308 thread is good.

BUT we do NEED a 308 AR forum
Link Posted: 1/25/2009 5:26:43 PM EST
This has been a most helpful thread.

I plan to convert an AR10 from an A2 stock to a collapsible.

Does the replacement carbine buffer tube have to be mil-spec. diameter or will a commercial diameter carbine tube work if that is all I can find?

Can I reliably use my AR10 rifle length buffer spring with a AR10 carbine buffer or is carbine length buffer spring mandatory?

Has anyone tried a Magpul UBR stock system (complete with their integral buffer tube) on an AR10?

Lastly, is the PRI charging handle interchangeable?
Thanks in advance.

Link Posted: 1/25/2009 9:00:59 PM EST
Originally Posted By Blackstone:

Does the replacement carbine buffer tube have to be mil-spec. diameter or will a commercial diameter carbine tube work if that is all I can find?

they are only different on the outer diameters-internal are the same

Can I reliably use my AR10 rifle length buffer spring with a AR10 carbine buffer or is carbine length buffer spring mandatory?

they are the same

Has anyone tried a Magpul UBR stock system (complete with their integral buffer tube) on an AR10?

need a slash buffer thats all



Lastly, is the PRI charging handle interchangeable?

works-get the sr25/ar10 vesion

Thanks in advance.

Link Posted: 2/24/2009 11:29:01 AM EST
Bushmaster Action Block on a AR-10

Link Posted: 2/25/2009 12:35:10 AM EST
Thanks for the pic

Link Posted: 2/28/2009 11:22:12 AM EST
[Last Edit: DuraCoater] [#48]
ArmaLite AR-10 Barrel Extension W/ Ext Ramps, does anyone have a pic of these ramps? I got a used 16" barrel and is looks like the center lug has been ground down to make a wide mouth feed ramp. the whole Thing is not gone just the front part of the center lower lug on the barrel exten. Also there are these markings on the chamber N10A

DPMS barrels

AR 10 barrel

Link Posted: 8/2/2009 7:01:57 AM EST
[Last Edit: Falar] [#49]
Originally Posted By TaylorWSO:

18. What FF tubes can I use on my AR10? Will a AR15 tube work?

You cannot use a AR15 tube because of the larger barrel nut on the 10. You also cannot use DPMS FF tubes as the barrel nut threads are different. Armalite uses 18tpi threads and DPMS/KAC use 16tpi. You can use a KAC FF tube on a AR10 but it will be longer than a AR10 FF tube and there "may" be problems with the gas block.  

I'm interested in putting a KAC URX II on an AR10 and am a bit confused by this.  The KAC tubes will fit, but simply won't thread on all the way because of the difference in threads?  If I'm reading this right, I still wonder if doing so would be bad idea.
Link Posted: 8/2/2009 3:40:41 PM EST
[Last Edit: TaylorWSO] [#50]
Originally Posted By Falar:
Originally Posted By TaylorWSO:

18. What FF tubes can I use on my AR10? Will a AR15 tube work?

You cannot use a AR15 tube because of the larger barrel nut on the 10. You also cannot use DPMS FF tubes as the barrel nut threads are different. Armalite uses 18tpi threads and DPMS/KAC use 16tpi. You can use a KAC FF tube on a AR10 but it will be longer than a AR10 FF tube and there "may" be problems with the gas block.  

I'm interested in putting a KAC URX II on an AR10 and am a bit confused by this.  The KAC tubes will fit, but simply won't thread on all the way because of the difference in threads?  If I'm reading this right, I still wonder if doing so would be bad idea.

I only put the KAC stuff in there because someone said it was possible, . I dont have personal experiance with it

Maybe its not, I will remove that infor until I find out more

here a post

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