Thanks, that's what I needed to know.

$50 to cut and thread.

what are the keymod options for ar10 platform?

I can only find MI keymod on a simple google search.

Okay, here's another question.  I have come to the realization that AR10s are not nearly as standardized as AR15s.  I looked at Rainer arms website and found two 12.5" barrels.  One was their brand, and the other was the Noveske leonidas.  They clearly have gas ports drilled at different locations, with the leonidas looking like it's a midlength.  Also, I've also noticed that manufacturers are not on the same page as to what length carbine and midlength gas systems are with AR10s.

So when you say it needs to be a carbine length gas system do you mean the hole is drilled at 7" or 9" or something else?

Thanks again

Noveske used a different length that they though was best if I remember right. There used to be two main patterns which were the Armalite AR10 and the DPMS LR308.

There are quite a few more now so make sure and do your homework.

the ranier is a true carbine length
the noveske is a PROPRIETARY length gas system- intermediate between carbine and mid length (a little bit softer shooting than the carbine length, i guess)

that is right.  It is about right in the middle of carbine and mid length.  

you might be able to get noveskie to sell you one of those gas tubes if you want to use it on a custom barrel.

also, you can just cut a longer gas tube to length and have adco or whomever drill the gas port accordingly on a cut down rifle barrel or another barrel whose gas port has been moved.  

everyone thinks that there is a swelled tip on the end of the gas tube; it's an optical illusion, the widest point of the tip of the gas tube is no wider than the rest of the tube.  The dong head shape is a result of the tip of the tube being rounded and then a little neck being sanded out of it to give it that look penisy look.  The purpose of the roudned tip is so the tip will slide into the gas key nice and easy and the purpose of the releive behind the glans shape is to make seal and reduce friction in their interface in case they don't go together perfectly straight.  It is easy to get this effect w/ a little sand paper if you need a custom length tube.  Its just brakeline unless you want one of those iconel ones.

He said "penis" in a tech forum. Lol

Posted Via AR15.Com Mobile

yeah, so there are lots of nuabce nowadays but there were two basic patterns of large frame AR10 type ARs on the civilian market since the 90s (or at least there were before DPMS came out w/ the G2).  The two patterns are the KAC pattern from the early 90s (often misnamed as DPMS pattern) and the Eagle Arms/"Armalite" pattern from a few years later. This of course excludes the original AR10s from the 50s but those are all collector peices, not ones people mod today.  

So, the main diffferences b/t the KAC pattern, which was shortly copied by DPMS, and the Armalite pattern guns are:
-Magazine: KAC used the original pattern magazine from the 1950s guns.  Armalite, more aimed at the civilian market during the awful AWB years (fuck you clinton) made their guns to use a modified M14/M1A magazine since the non banned original pattern magazines were rare, expensive, and many of them were flimsy old waffel mags.  
-Carrier/Bolt/Barrel extensino:  so theoretically some people say that you can mix and match different barrel extensions, bolts and carriers, or some of those parts b/t  Armalite and DPMS guns, others argue that this often cause problems, potentially big problems and shoudl never be done.  I don't really understand the details, but the main thing you need to know is that mixing, for example, an Armalite pattern carrier w/ a DPMS barrel extension, or an armalite bolt w/ a KAC/DPMS carrier...that doing eitehr of these types of things is contriversial.  THe non contriversial thing is to use either a KAC/DPMS or an Armalite pattern carrier, bolt, and barrel extension.
-Upper receiver threads: different length and pitch so the handguard sytsms are not interchangable.  ALso, at some point DPMS made their upper receiver rails higher or lower, so there are two patterns of handguards for generation 1 DPMS upper receivers.
-bolt catch: Armalite uses a proprietary beefier bolt hold open/catch.  THe KAC/DPMS used one from an AR15.  

Since the 90's where it was eitehr KAC/DPMS or Armalite, there are lots of makers who have lots of various propritary parts or dimensinos.  No though, most everyone is agreed on the original pattern AR10 magazine, NOT the eagle arms ("armalite") M14 based design.  Even Armalite makes rifles for the original pattern mags and will probably stop making their "B" pattern receiver sets that use their excellent M14 based magazines, which is a shame since they are really great mags once they were able to make new mags and stop monkey fucking around w/ modifying M14 magazinew which had mixed results.

DPMS pattern is different than KAC.  They use the same mags, and most of the internals are similar or interchangeable, but the receivers are different.  KAC uses a slanted rear cut like the original AR10 and the new AR10s.  DPMS uses a rounded rear cut like the AR15.  This was all before the GII of course.

yes noveske used the intermediate length gas tube , it was developed by vltor for use on 18" barrels then tweaked by noveske.  John Noveske was ahead of the curve when it came to the ar platform

you can pick one up from midway usa for under $12

http://www.midwayusa.com/product/234178/noveske-gas-tube-intermediate-length-ar-15

That intermediate is between mid and rifle and longer than the KAC pattern mid.

This is between mid and carbine, though I'm told that KAC has prototyped something like that in 5.56mm too.

Almost exactly like this is what I'm thinking..... Maybe in Multicam to match my mk18

I've got to admit I have a serious lust for something like this. I am stunned how many options there are for something like is now. I have been lusting after the sig 716 pistol for awhile and I think Atlantic firearms is selling a 10 or so inch barrel version of the PTR 91 308 "pistol" with a brace.

I have a bad feeling that if I ever got to shoot one of these short barrel 308s my wallet would never forgive me.

well i built a 12.5 that is a mid gas system. i have not been able to take it out yet but hopefully it runs good. the barrel is a cmmg 12.5.
i hope i dont have to buy  another barrel . fingers crossed

Adco can relocate the gas port if it comes to it.  

I recall that ARP sells 12.5" middys which apparently work alright, not in 308 tho.

I heard about a guy who tried to do like a 13.5" from a n armalite middy and had problems w it, dont kno if he ever got it running

I had an 8.5" ptr 91 pistol.  Was really holding it for a guy till he repaid a loan.  Twas hella heavy.  Same w a sig 716 though it would balance a little better.  Id recommend an ar w a stoner gas system.

Thanks for all the replies, very helpful.



Let us know how it works, I'm curious.

Only thing I dislike is the cost of ammo for the .308s.
" />

I Have a Full Noveske 12.5 Leonidas . It was kinda of difficult to get them back in 2009 -10  when I purchased mine.
I ran mine in a local outlaw 3 Gun match and it just ran . Heavy bastard  with 25 round  mags but it was awesome .  Have a AAC SN6 mounted to it now .  7.62 SBR Suppressed is the Shi!!!! will try and get a pic posted .

I'm thinking of doing a Mega Maten MKM keymod rifle length with the mid-length CMMG barrel.  

Waiting to hear the range report on the guy with the same barrel above.  

Also, Mega states that the rail is 12".  Will this cover the 12.5" CMMG barrel?

it would.  rifle handguard are about 12.5" from front of the receiver.  

barrelles, as measured from the breech (bolt) face start about 1/4" behind the front edge of the upper, by front of the receiver, I mean the visible part where the rail ends, not the threaded part under hte barrel nut

So, would the MKM Rifle length rail not work with that barrel, then?

and they were hitting the 1000 meter target at midnight...

I hear a lot of griping about those quals.

and they have even made it easier already once....not going to happen again I am told...

sure it would work w/ the barrel.   whether it would work w/ the muzzle device or not is the question.  A lot of guys run handguard past their shoulder or muzzle, so long as the end of the muzzle device runs out a little past the end of the hand guard for safety it is fine if the barrel is shorter than the handguard.  But some type of suppressor quitek detach mounts need to have the shoulder exposed, even if your handguard ID could accomidate the can, you need it exposed to access a button or whatever.

Palmetto has a complete 308 PA10 pistol lower for $250 & with their carbine complete upper, hack saw & files for the crown your in for $680 + Sig Brace ala 716



http://palmettostatearmory.com/index.php/ar-10/lowers/psa-pa10-308-complete-pistol-lower.html

http://palmettostatearmory.com/index.php/catalog/product/view/id/18334/s/ptac-16-carbine-length-308-upper-with-bcg-and-charging-handle/category/4376/

Thanks for the reply.  I guess it doesn't matter, because I live in Illinois.

Here is this308  upper KAK is selling, 10.5'" barrel w/ their flash can cone type Muzzle device an a normal rifle lenght Midwest industries hand guard:


if suppression is not an option and you want to rock out w/ your cock out and kill the enemy w/ concussion if you miss w/ the bullet

Any of y'all with 12.5 inch guns have y'all chronographed any loads? Would you shoot a small white tail within 300 yards? (I've killed plenty of whitetail at 100 yards and below with a 10.3 inch 5.56 AR.)


RC

i do not have chromo, I  seem to recall some data on 12" POF rifle showing 168 or 175 GMM at >2400 fps.  maybe its on their site?

I'm looking at book data right now for 22" service rifle, and it lists max loads at 2400fps with the 178gr.

For a 22" bolt gun, it's listing 2500fps as a max load with a 178gr.  2700fps with a 168gr from a 22" barrel.

That's 9.5" more barrel than a 12.5" AR10.  There have been younger, bolder reloaders who told me they could easily spit a 185gr Berger from a 12.5" AR10 at 2300fps.  I used to be young and bold too, and AR10's are pretty forgiving of stupidity.  I look for lower pressures now, not higher.

must be remembering incorrectly.  

pilot, google 12" 308 ballistics  or similar and you'll find some stuff

My friend is looking to hunt white tail within 300 yards with his 12.5" build as well.  It's not done, so no chrono results, but here are the numbers I came up with on a ballistic calculator.  Should be close enough.  Seems to me like it will do just fine under 300yds.

The load isn't at max according to Hodgon either.  So you could push a little more out of it.

a 16" 7.62x39 or 300 blackout is probably lighter and handier and roughly the same length as a 12.5" 7.62x51.



ballistics are probably not too far off either.  just saying.

Not even close on either account.  I'm not even sure how you think they would be the same length.  Also, I already have a SBR in 300blk.  That's for suppressed use as far as I'm concerned.  I can't remember the last time I shot it with anything but subsonics through a can.

As for ballistics, here you go.  Both with the same 150gn projectile. The 308 has more energy at 300yds than the blackout at 100.

300BLK out of 16" barrel
100yds = 1653fps 910ft/lbs energy
200yds = 1515fps 765ft/lbs energy
300yds = 1390fps 643ft/lbs energy

308 out of 12.5" barrel
100yds = 2269fps 1714ft/lbs energy
200yds = 2097fps 1465ft/lbs energy
300yds = 1933fps 1244ft/lbs energy

WFT you talking about, ballistics of either in 16" aren't close to a 12.5" 308.  

AR10s are about 1 1/4" longer than an Ar15 of same barrel length.  IIRC, AK receivers are as long as AR10 reeivers.