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Posted: 2/21/2006 12:17:21 AM EDT
[Last Edit: 2/21/2006 12:24:41 AM EDT by Variablebinary]
I have a Rock Entry Tactical that I want to turn into a MK12 Mod 0 SPR clone

Can you list the parts, approx prices and location where I can score what I need. I want the end product to resemble the photo below.

I dont need the Ops INC collar or brake, I will be mounting a phantom.

Would a middy 16" be okay in place of a 18" SPR, or will I degrade long range performance

Is the MK 12 Mod 0 SPR a solid 500-600 yard minute of head/dead weapon?

Here is the illustration that is my inspiration, only I will lose the A2 stock and use a Magpul PRS


Link Posted: 2/21/2006 12:49:55 AM EDT
With all due respect, the weapon that you are talking about barely resembles the SPR. Why not get one of MSTNs precision uppers. Skip the SWAN sleeve, get a Larue rail, and a 16 inch barrel. The assembly will be lighter, possibly cheaper and much better looking, if that is your goal.
Link Posted: 2/21/2006 2:02:17 AM EDT
Link Posted: 2/21/2006 4:13:42 AM EDT
look up adcofirearms or mstn in the industry forum. there is lots of info there and they are two good spr builders.
Link Posted: 2/21/2006 5:17:17 AM EDT
Real SPR uppers are available... but very spendy, I can get them as can Steve from ADCO, but Steve can get you an SPR clone that is soooooooo close to being the real thing that it really is sort of funny.

Some more of the Enhanced SPR uppers were just done, but may all be spoken for... have to check. in any case, I would hit up Steve at ADCO -- complete upper, parts or just talk to someone that knows what they are talking about (that last thing being a reare find really).

Link Posted: 2/21/2006 5:27:27 AM EDT
This is from an SPR article out of Combat Tactics magazine, Sept 2005.



Link Posted: 2/21/2006 7:05:28 AM EDT
I would contact Adco.

They are biulding some of the nicest SPR's around.
Link Posted: 2/21/2006 7:12:36 AM EDT
What is Stag supplying for the SPR? Upper reciever and BCG?
Link Posted: 2/21/2006 7:14:17 AM EDT

Originally Posted By Variablebinary:
I have a Rock Entry Tactical that I want to turn into a MK12 Mod 0 SPR clone

Can you list the parts, approx prices and location where I can score what I need. I want the end product to resemble the photo below.

I dont need the Ops INC collar or brake, I will be mounting a phantom.

Would a middy 16" be okay in place of a 18" SPR, or will I degrade long range performance

Is the MK 12 Mod 0 SPR a solid 500-600 yard minute of head/dead weapon?

Here is the illustration that is my inspiration, only I will lose the A2 stock and use a Magpul PRS

www.dogfightink.com/SPR.jpg



Doesn't the red above negate a REAL SPR clone?

Link Posted: 2/21/2006 7:15:19 AM EDT
Link Posted: 2/21/2006 7:17:07 AM EDT

Originally Posted By Combat_Jack:
With all due respect, the weapon that you are talking about barely resembles the SPR. Why not get one of MSTNs precision uppers. Skip the SWAN sleeve, get a Larue rail, and a 16 inch barrel. The assembly will be lighter, possibly cheaper and much better looking, if that is your goal.



Why doesn't it resemble a Mk12Mod0 SPR?

IIRC Mod 0's had the PRI carbon tube, and were built on M16A1 lowers.
The Mod 1's had the DD rails and some flavor of collapsable buttstock.
Link Posted: 2/21/2006 7:22:14 AM EDT
I'll contact ADCO and MSTN. For those that built their SPR uppers, what was the cost in the end?

What kind of accuracy can I expect shooting M855?
Link Posted: 2/21/2006 7:24:32 AM EDT

Originally Posted By bigbore:

Originally Posted By NUcadet07:
What is Stag supplying for the SPR? Upper reciever and BCG?



Nothing for the real ones...



I don’t know why Stag is mentioned there in the specs. I thumbed through the entire article again and found no mention of Stag at all.
Link Posted: 2/21/2006 7:29:04 AM EDT
[Last Edit: 2/21/2006 7:29:43 AM EDT by bigbore]
Link Posted: 2/21/2006 7:31:52 AM EDT
It sounds like you want a "REECE" and not an SPR.

Link Posted: 2/21/2006 7:34:11 AM EDT
[Last Edit: 2/21/2006 7:37:57 AM EDT by chapperjoe]
I got a custom rifle instead of going full out SPR with all the proper SPR or Recce specs.

An industry partner built it for me himself and I added a few used parts.

Total Price with EVERYTHING came out to about 16-1700. An SPR could easily double that or more.

Ameetec upper and lower (which industry partner, hmmmmm.... ) with 18" fluted prototype barrel mid-length gas system with a vortex on the end. PRI low gas block with a samson rifle length rail over it and a harris 6-9 no swivel yes notches. Chrome bolt carrier, bolt group etc. Rock River dual stage trigger, magpul trigger guard, SPR grip, VLTOR A1 clubfoot stock. DPMS mangonel front sight, troy rear, LArue 5/8" QD riser with a super sniper on Loopy QRW rings.

Ammo will be 75 and 77 gr black hills exclusively (some blue some red) and I hope to make tiiiiiny little groups of holes.
Link Posted: 2/21/2006 7:36:52 AM EDT

Originally Posted By bigbore:

Originally Posted By NUcadet07:
What is Stag supplying for the SPR? Upper reciever and BCG?



Nothing for the real ones...



acc to your thread, upper and lower seemed std, am i right?
Link Posted: 2/21/2006 7:56:27 AM EDT

Originally Posted By bigbore:

Originally Posted By Variablebinary:
What kind of accuracy can I expect shooting M855?



You should hit a Grapefruit at 100yds.

If you arent going to be buying match ammo, dont waste your money on an upper built to shoot match ammo.


If you are building something to look cool; have fun, but be realistic in you expectations.

IMO, if you are going to be shooting ball ammo, just get a standard, chrome-moly barrel, and spend the extra money on ammo.



The goal really is to build a 500-600 yard AR15. If that requires 75 and 77 gr match ammo that is fine. I just have about 2000 rounds of M855 sitting in the closet.

Can you do a conversion on an RRA upper into a MK12 Mod 0 with some minor changes? Also what is the turnaround time on getting SPR MK12 Mod 0 uppers from adco currently?
Link Posted: 2/21/2006 8:02:21 AM EDT

Originally Posted By sic_ness:

Originally Posted By Combat_Jack:
With all due respect, the weapon that you are talking about barely resembles the SPR. Why not get one of MSTNs precision uppers. Skip the SWAN sleeve, get a Larue rail, and a 16 inch barrel. The assembly will be lighter, possibly cheaper and much better looking, if that is your goal.



Why doesn't it resemble a Mk12Mod0 SPR?

IIRC Mod 0's had the PRI carbon tube, and were built on M16A1 lowers.
The Mod 1's had the DD rails and some flavor of collapsable buttstock.



The only similarities that his desired configuration would retain are the PRI float tube and a plethora of ARMS paraphenalia. A Recce can do most of the same things, and is actually more similar to what he was talking about getting.
Link Posted: 2/21/2006 8:07:22 AM EDT
Link Posted: 2/21/2006 8:07:39 AM EDT

Originally Posted By Combat_Jack:

Originally Posted By sic_ness:

Originally Posted By Combat_Jack:
With all due respect, the weapon that you are talking about barely resembles the SPR. Why not get one of MSTNs precision uppers. Skip the SWAN sleeve, get a Larue rail, and a 16 inch barrel. The assembly will be lighter, possibly cheaper and much better looking, if that is your goal.



Why doesn't it resemble a Mk12Mod0 SPR?

IIRC Mod 0's had the PRI carbon tube, and were built on M16A1 lowers.
The Mod 1's had the DD rails and some flavor of collapsable buttstock.



The only similarities that his desired configuration would retain are the PRI float tube and a plethora of ARMS paraphenalia. A Recce can do most of the same things, and is actually more similar to what he was talking about getting.



Someone remind me again what the differences are between a Recce and SPR are
Link Posted: 2/21/2006 8:28:03 AM EDT
Here is a real SPR
[ link to LARGER image ]
Link Posted: 2/21/2006 8:47:32 AM EDT
Recces tend to be shorter, lighter and more carbine-like. The big difference is in the optic. You are going to want a bigger one than a true Recce would have.

The SPR is type-classified, the Recce is a more fluid concept.

My main point is that just cause the Army uses (although they don't all necessarily like) the SPR doesn't mean it is what you want to build.
Link Posted: 2/21/2006 9:14:34 AM EDT
I got the pri tube, front and rear buis from http://www.oriontacticalgear.com/PRI.html
he has the best prices and free shipping. also great customer service.
the arms rings, PRI gas buster charging handle, and SPR PEQ 2-3 rail from www.adcofirearms.com you can also get the white oak armament SPR barrel from him as well I also think he sells the ops inc. break.
If you have any more questions email me.
Link Posted: 2/21/2006 9:25:27 AM EDT
[Last Edit: 2/21/2006 9:26:42 AM EDT by conndcj]
One more build down and one more to go. My version of an SPR came out great with the minor exception of having to go with a 4 port Ops Inc brake instead of the correct military 2 port with the collar. Some day before I die.

Colt upper
KAC lower w/KAC two stage trigger
Noveske 18' SS, poly 1/7 w/ 5.56 match chamber, PRI Mod O contour
PRI Gen III CF tube
PRI front sight
ARMS PEQ2A rail w/40L BUIS
Rock SOPMOD bipod
Magpul PRS, MIAD and triggerguard
SF M972 in LT offset mount
NF 2.5-10 w/ NPR2 reticle in LT pount w/J-Point mount and J-Point

Target was set at 150yds and I shot 5 round groups off of a bench using the bipod. Ammo was MK262. The rifle flat out shoots, no doubt about it. Noveske barrels are smoking good. I have seen some of ADCO's and MSTN's work as well. They both really know their stuff and you couldn't go wrong with either.

http://i20.photobucket.com/albums/b243/conndcj/SPR01.jpg

http://i20.photobucket.com/albums/b243/conndcj/SPR02.jpg

http://i20.photobucket.com/albums/b243/conndcj/SPR03.jpg

http://i20.photobucket.com/albums/b243/conndcj/SPR04.jpg

http://i20.photobucket.com/albums/b243/conndcj/SPR05.jpg
Link Posted: 2/21/2006 9:35:58 AM EDT

Originally Posted By QUIB:
This is from an SPR article out of Combat Tactics magazine, Sept 2005.

www.hunt101.com/img/379589-big.jpg

www.hunt101.com/img/379588-big.jpg



That SPR was built for the article and is not to spec. Stag and Surefire are NOT on the SPR menu.

Middys are an alternative to carbines, not rifles. You are considering 2 totally differnt rifles here. You certainly will lose velocity and range going from 18 to 16 inches, but it won't be a huge reduction.

But it's not clear if you want a built upper or if you want to do it yourself. You can save a lot of money by sourcing parts and doing the labor yourself, but there are some install techniiques unique to an SPR that you should be aware of. It isn't just a matter of slapping the parts on.
Link Posted: 2/21/2006 9:39:59 AM EDT
Link Posted: 2/21/2006 9:50:33 AM EDT
I thought the MK12's had KAC stuff...like the KAC FF rail etc....what rifle has those?
Link Posted: 2/21/2006 9:55:18 AM EDT
[Last Edit: 2/21/2006 9:56:33 AM EDT by SWO_daddy]
If you want the SPR tacticool look, have at it, but 90% of the stuff on an SPR is completely unnecessary for building an AR that will group MOA or less at 600 yards.

A Krieger or Pac-Nor 1/8 barreled varmint upper from White Oak Precision, a good scope and rings, and a Geissele trigger in your lower is all you need. The rest of the stuff are peripherals that do nothing to improve accuracy.
Link Posted: 2/21/2006 10:29:49 AM EDT
[Last Edit: 2/21/2006 10:34:08 AM EDT by Variablebinary]

Originally Posted By SWO_daddy:
If you want the SPR tacticool look, have at it, but 90% of the stuff on an SPR is completely unnecessary for building an AR that will group MOA or less at 600 yards.

A Krieger or Pac-Nor 1/8 barreled varmint upper from White Oak Precision, a good scope and rings, and a Geissele trigger in your lower is all you need. The rest of the stuff are peripherals that do nothing to improve accuracy.



I'm toying with ways to simplify the design and shave cost, but maintain some level of easiness on the eyes. I came up with something I think fits okay

16" Dissy SPR. Should be much cheaper to make than a real SPR upper and give me what I need.
Is this config possible? I would need a free float rail that doesnt require the fsb to be butchered or removed

Link Posted: 2/21/2006 10:33:04 AM EDT
It probably won't work as well as a 16 inch mid-length would due to timing issues. And be sure to get a float rail, there is the possibility of POI shift with a non-float rail.

Save the money on the SWAN sleeve/ARMS rings and get a Larue mount and if you want buy a cheap 100 dollar float tube.
Link Posted: 2/21/2006 10:34:55 AM EDT
What timing issues?
Link Posted: 2/21/2006 10:39:51 AM EDT
You could use a troys float tube for that I think but I would not do a dissy when there is sooo much more out there to choose from.
Link Posted: 2/21/2006 10:40:05 AM EDT
Link Posted: 2/21/2006 10:41:28 AM EDT
Will that realy play a factor if it is not select fire? Is there something I am missing? My M4 fires fine, even on burst, is it something about a dissipator?
Link Posted: 2/21/2006 10:58:28 AM EDT
it all depends on the kool-aid you drink, the wonder of the firearms. You design exactly what you want...

here was my take on the SPR



Upper
Bushmaster Upper
LMT Enhanced Bolt Carrier
Colt Bolt (gauged by Dave at PRi to fit my chamber, since the CMT wouldn't fit, funny eh?)
CMT Charging Handle
ABS 18inch Carbon Fiber Barrel, .223 Wylde Chamber, Pacnor super-match SS, 1:8twist
PRi low profile, rifle positioned gas block
PRi Gen III carbon fiber fore-end, small rails at 6/12 o'clock positions
MSTN Quiet Brake
Harris 6-9 pod-lock w/larue QD mount

Lower:
Bushmaster lower
SOPMOD Stock
MIAD Grip/trigger guard with internal backup LMT Bolt and firing pin
Geissele Match 2-stage Trigger, 4lbs total, last stage at 1lb


Optics:
SN-3 1.8-10x, 44ergo objective, MOA Illuminated Reticle, .223 BDC, mounted in the Larue SPR
Jpoint 3.5moa red-dot on top of the Larue Mount
Troy Front and Rear BUIS
Link Posted: 2/21/2006 10:59:59 AM EDT

Originally Posted By DM1975:
Will that realy play a factor if it is not select fire? Is there something I am missing? My M4 fires fine, even on burst, is it something about a dissipator?


You need to understand the relationship between barrel length and has port location.
Link Posted: 2/21/2006 11:04:12 AM EDT
So my 14.5 inch barrel and carbine length gas system will have less dwell that a dissipator. I dont know anything about dissys is why I am asking, not trying to start a flame war or anything like that.
Link Posted: 2/21/2006 11:07:17 AM EDT

16" Dissy SPR. Should be much cheaper to make than a real SPR upper and give me what I need.
Is this config possible? I would need a free float rail that doesnt require the fsb to be butchered or removed /quote]
Originally Posted By DM1975:
So my 14.5 inch barrel and carbine length gas system will have less dwell that a dissipator. I dont know anything about dissys is why I am asking, not trying to start a flame war or anything like that.


The Bushmaster Dissipator has a carbine gas system and a 16" barrel.

Link Posted: 2/21/2006 11:08:10 AM EDT
So in a semi auto rifle what would the effects be?
Link Posted: 2/21/2006 11:50:46 AM EDT

Originally Posted By Variablebinary:

Originally Posted By SWO_daddy:
If you want the SPR tacticool look, have at it, but 90% of the stuff on an SPR is completely unnecessary for building an AR that will group MOA or less at 600 yards.

A Krieger or Pac-Nor 1/8 barreled varmint upper from White Oak Precision, a good scope and rings, and a Geissele trigger in your lower is all you need. The rest of the stuff are peripherals that do nothing to improve accuracy.



I'm toying with ways to simplify the design and shave cost, but maintain some level of easiness on the eyes. I came up with something I think fits okay

16" Dissy SPR. Should be much cheaper to make than a real SPR upper and give me what I need.
Is this config possible? I would need a free float rail that doesnt require the fsb to be butchered or removed

www.mstarmetro.net/~acouret/SPR%20custom.JPG



Dude! What the hell did you do?
Link Posted: 2/21/2006 2:06:06 PM EDT
Buy a RRA NM A2 and learn how to shoot.
Link Posted: 2/21/2006 2:09:01 PM EDT

Originally Posted By warren-hpf:
Buy a RRA NM A2 and learn how to shoot.



Thats an expensive gun to learn how to shoot on.
Link Posted: 2/21/2006 2:10:25 PM EDT

Originally Posted By chapperjoe:

Originally Posted By warren-hpf:
Buy a RRA NM A2 and learn how to shoot.



Thats an expensive gun to learn how to shoot on.



If the goal is for a 600 yard rifle, then a RRA NM A2 will do that out of the box. Well, you need a sling, but otherwise...
Link Posted: 2/21/2006 2:16:19 PM EDT

Originally Posted By warren-hpf:

Originally Posted By chapperjoe:

Originally Posted By warren-hpf:
Buy a RRA NM A2 and learn how to shoot.



Thats an expensive gun to learn how to shoot on.



If the goal is for a 600 yard rifle, then a RRA NM A2 will do that out of the box. Well, you need a sling, but otherwise...



oh ok yeah no doubt. to learn how to shoot at 060 yeards the simple way, definitely RRA nm A2. Then again, oince you master that, who needs a damn scope or SPR!
Link Posted: 2/21/2006 2:38:34 PM EDT
[Last Edit: 2/21/2006 2:41:26 PM EDT by SWO_daddy]

Originally Posted By chapperjoe:

Originally Posted By warren-hpf:
Buy a RRA NM A2 and learn how to shoot.



Thats an expensive gun to learn how to shoot on.


A hell of a lot cheaper than an SPR clone, I'll tell you that right now.

Besides, it is foolish to buy an inaccurate rifle and poor quality ammo to learn to shoot. A novice is the one who benefits the most from the most accurate rifle and ammo combination, since such combination removes the most variables from the equation and provides the most accurate feedback to the shooter.
Link Posted: 2/21/2006 10:48:35 PM EDT

Originally Posted By Homeinvader:

That SPR was built for the article and is not to spec. Stag and Surefire are NOT on the SPR menu.

Middys are an alternative to carbines, not rifles. You are considering 2 totally differnt rifles here. You certainly will lose velocity and range going from 18 to 16 inches, but it won't be a huge reduction.

But it's not clear if you want a built upper or if you want to do it yourself. You can save a lot of money by sourcing parts and doing the labor yourself, but there are some install techniiques unique to an SPR that you should be aware of. It isn't just a matter of slapping the parts on.



Can you be a little bit more specific on the subject, please.
Link Posted: 2/22/2006 12:05:13 AM EDT
Just for general info and ref....
http://en.wikipedia.org/wiki/United_States_Navy_Mark_12_Mod_X_Special_Purpose_Rifle
Link Posted: 2/22/2006 6:46:17 AM EDT
I just want to know who did those illustrations.....
Link Posted: 2/22/2006 6:57:01 AM EDT
[Last Edit: 2/22/2006 6:57:35 AM EDT by kemp]

Originally Posted By WiseguyThreeOne:
I just want to know who did those illustrations.....



He's a couple of posts up. Dogfight Ink :)
Link Posted: 2/22/2006 7:36:10 AM EDT
some thoughts on timing, dwell and all of that.... From this thread. BTW: Midlength Dissy is a nice rig!


In order to understand this, there are a few things about the functioning of the AR that have to be defined, I am away from most of my notes and stuff, so most of the figures given are from memory... but should be pretty close. For this description, the standard rifle gas system is with the gas port located at 13.0" and having a 20" barrel... the standard carbine system is with the port at 7.5" and a barrel of 14.5"

The pressures at the gas ports are: 13.5K for the rifle and 26K for the carbine -- or twice as much.

The dwell time (the time that the gas system is charged with high pressure) is determined by the amount of barrel after the gas port. These are nearly identical between the rifle and the carbine.

Pressure from the port is regulated only by the size of the gas port and the diameter of the barrel.

These two factors determine the internal bolt pressure, the maximum pressure that is obtained in the bolt carrier/piston combination -- for the rifle this pressure is about 1000psi and for the carbine it is over 1500psi, half again as much.

When the rifle is fired, primer shot sets the bullet forward until it contacts the rifling, at this point the powder charge detonates and sets the shell case fully back, binds the action and start to propel the bullet. The bullet jumps slightly again and is etched by the rifling... it stops again very briefly as the pressures build to a point for the bullet to overcome the mechanical advantage of the rifling twist and the bullet starts to spin, at this point the chamber pressure is at max, 50K plus (there are some that believe there is another, third stop the bullet makes and some testing suggest this may be true).

As the chamber pressures start to climb, the brass case expands and becomes plastic, this is essential to seal the case in the chamber -- the correct term for this is Obturation, when the case is obturated and sealed, it is stuck in the chamber, practically welded in really.

The Lock Time, or the time that the action remains locked with no attempt to start unlocking is very important... on the rifle, the lock time is about 550 microseconds, the lock time for the carbine is about 375 microseconds -- this may not seem like much, but it is much shorter of a time, also keep mind that the chamber pressures are twice as high in the carbine when the unlocking starts.

What does all of this mean? When the carbine is fired, the system attempts to unlock earlier than intended and while the case is still fully obfucated... this results in the action bind delaying the unlocking and stressing the system. As the 5.56N is not drastically tapered, "squirting" is not a big problem in most guns. When the internal bolt pressures finally unlock the bolt, the velocity of the reward movement in the carbine is much higher than what the rifle was designed for, it also must start extraction of the obfucated case... as you know, the AR does not have any sort of initial extraction, perhaps the single biggest shortcoming of the design. This has been known to cause ripped case heads...

At this point, as the bolt start to unlock, it is rotated to unlock... due to much higher velocities with the carbine, the rotation of the bolt creates enough centrifical force to "float" the extractor... the extractor on the AR is not balanced and the forward part of it weighs more -- some argue that the pressure of the extracted cartridge case keeps the case head against the bolt face, but the fact is that the extractor does float and the contact with the case rim becomes "soft". For this reason, it is much more likely that the extractor will simply pop off, rather than actually rip the case.

Balanced extractors and different designs have been developed (LMT), but the best solution to date has been stronger extractor springs and spring buffers. That about covers the FTE issues...

Back to bolt velocity. The high speed of the bolt has a couple of other detrimental effects, one of the most common is that the bolt is cycled so fast that as it returns to battery, it actually has enough force to "bounce" off of the barrel extension when closing and locking... this bounce back is very small, but can be enough to cause the weapon not to fire... this "bolt bounce" is pretty well known.

One other problem is that the bolt can cycle so fast the magazine spring can not keep up with it and the round stack is not properly aligned and forced back into place before the bolt returns to batter -- therefore there is no new cartridge picked up and the bolt closes on an empty chamber, this is what some call "ghost loading", or bolt-over-base jams... this is far worse in full auto fire as the bolt does actually move faster in full auto than semi auto; this is due to the fact that the top cartridge in the magazine does not apply force to the bottom to the bolt causing drag.

The common solution to this issue is to use a stronger recoil spring and a heavier buffer... this works, but is treating the symptom, not the problem.

PigTail and expansion chamber gas tubes attempt to fool the rifle into thinking that the gas port is, located further away that it really is, but they are not as good of a solution as actually moving the gas port out...

I guess that about covers it for a quick rundown, of course all of this is not nearly as simple as it sounds.

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