Reliability: Is the AR10 there yet?

[Rogue7a]

We actually got to mess with all the submitted SAS rifles and decided to come up with our own.

Using a DPMS LR .308 (The one with the forward assist that Rem used which was on the property books from I don't know when) we took parts from all three guns (Armalite, KAC and Rem). This is what our build sheet consisted of:

1. DPMS LR .308 Receiver
2. Magpul Stock
3. Daniel Defense 12.0 Lite Rail
4. Kriger 1/10 20" BBL
5. Accuracy Speaks Trigger
6. Leupold M2 3.5-10x40mm TMR w/ illum reticle
7. ARMS #22 Medium Rings
8. OPS Inc. .30 cal 12th Model MBS
9. Armalite SASS Adjustable gas system
10. KAC Front and rear sights
11. GG&G Heavy Bipods.


During the build we had to mill the DD Rail System to fit the Armalite SASS Gas system but it was not much of a problem. We already had data on the Adjustable gas system settings for unsuppressed fire so all we had to do is strap on the can and work out a couple of issues. The gun is VERY capable using M118LR (AMU Loads) and is shooting aroud 1/2 moa. I however don't think that it will replace a good bolt gun anytime in the future.

[Lumpy196]

Just got back from the range (NRA).
Fired 60 rounds:

Flawless function.

Im glad you're pleased, sincerely.

However, THAT is exactly the type of report I get out of "happy" AR10 owners, and it proves absolutely nothing in terms of depend-your-life-on reliability.

[KevinB]

FWIW -- no 7.62mm Gas gun I know of works well.
IMHO (dislaimer being the local KAC cheerleader) I have been very impressed with the KAC Mk11 series guns I have shot.
My expeirences with Armalite and DPMS have been dismal.
Armalite in 24, 20 and 16" guns where ok in the accuracy dept but took a dump in the reliability dept -- (I'm talking a fair bit of shooting -- i.e. 1k of rounds in a less than a week -- which is nothing to a 5.56mm gun -- but the 7.62mm carbines ...)

DPMS barrel nuts are like peanut brittle - and we cracked four trying to replace the craptastic tube they came with with KAC FF RAS's for the SR25/Mk11.
Once we got them off it worked okay -- the KAC mags being the biggest plus.

I like (love) KAC -- but in the world of 7.62mm gas guns - I am very curious to see the Hk417 -- I am trying to add 4 of them to our Hk416 order.

[Zak Smith]

I owned a JP AR10 for over a year. I have friends with AR10's. I have seen probably 20-30 more of them at national- and local-level 3Gun matches over the last 4 years (trying to either shoot Major PF or He-Man / Heavy Metal division).

My own rough estimate is that 80-90% of them have taken a major dump during the matches, rendering them either unable to cycle, consistently jamming, or catastrophically failing. I know of precisely "two" AR-10's which run consistently provided good ammo.

My experience with my own AR10 and some friends' AR10's is that they tend to be ammunition sensitive with regard to both function and even moreso accuracy. Of all the factory 150-175gr ammo, mine would "only" group under 1" with 168gr FGMM.

The other thing I don't like about the AR10 is the huge reciprocating mass necessitated by the design. It's got to be 3-4x the weight of the recip mass in the AR15. All that slamming around does not help with sight picture reacquisition, or spotting one's own hits. In comparison, an M14 with its light bolt doesn't move at all.

I am looking forward to the SCAR-H as a viable modern 308 platform...

[Alpha Sierra]

Some experience from the non-tactical side of things.

Back in the 1997 - 1999 time frame, David Tubb tried to make the SR-25 in 6.5-08 work as a NRA Match Rifle. He had untold problems with broken parts of all sorts. It took several modifications to get it all to work. He finally won the National Championship with it on his third attempt in 1999. He decided that the gun was never going to be as accurate and as reliable as his bolt guns, so he ditched it and went back to the Model 70s he had so much success with.

Tubb did like the AR-15-like ergonomics so much that he incorporated them in his own-design bolt gun. While the TUBB2000 looks like an AR-10 turned into a bolt gun, it is not. It does not share the upper/lower receiver design of the AR series and the bolt design is completely different.

Target version:



Tactical version:

[Rogue7a]

FWIW -- no 7.62mm Gas gun I know of works well.

Yeah we had jams every 500 rds (suppressed) but was rectified by cleaning the chamber. Not bad considering it is a "Precision" weapon. I think it would have to be "Zulu dawn" to have to fire that much from a Sniper Rifle (Experiance coming from my 4 tours in said role). Without the can it was all energizer bunny. The stoppages with the can were consistant with the official tests.

[az_gun_nut]

The other thing I don't like about the AR10 is the huge reciprocating mass necessitated by the design. It's got to be 3-4x the weight of the recip mass in the AR15. All that slamming around does not help with sight picture reacquisition, or spotting one's own hits. In comparison, an M14 with its light bolt doesn't move at all.

I am looking forward to the SCAR-H as a viable modern 308 platform...

I think you forgot about that operating rod that is attached to that light bolt. Figure in ALL that mass and you are no lighter than an AR10.

I've shot M14's in full and semi auto and fullauto G3's. The G3 handled better than the M14's by far, Heavier weapon, heavier bolt mass and could be held on target and a full mag dumped, can't say the same with the lighter M14.

My buddies Armalite AR10T runs great on South African, but then again I've yet to come across one bad round in the couple thousand I've shot of SA as well.

The only issue we had with his Armalite was a loose gas key. Cleaned and reinstalled, retorqued and restaked and it's been running great.

[Zak Smith]

The M14 has far less reciprocating mass than the AR-10, and it is evident by observing the various inertia events during recoil.

[az_gun_nut]

The M14 has far less reciprocating mass than the AR-10, and it is evident by observing the various inertia events during recoil.

Please be more specific, what inertia events and how do they affect felt recoil and being able to get back on target quicker or slower?

In my humble experience I've shot both and although I love the M14, (might be that Marine corp grunt image) but I would choose a well set up AR10 first. A decent muzzle brake will tame any muzzle jump, the right combination of buffer weight and gas port size will tame the hard "slamming" recoil as some call it.

Just my. 02 worth.

[Zak Smith]

I have run and seen run all combinations of gas port tuning in the AR-10. There is no getting around that heavy bolt carrier group (and to a lesser extent the buffer) moving around, and it has a long throw.

To stay on target all other things equal (rifle weight and muzzle device), one wants less reciprocating mass and for the action events to be over sooner.

The AR-10 BCG+buffer must travel all that way to the rear, slam into the receiver extension, and then go forward and slam into battery. If you slow it down with less gas pressure, the now the whole operation takes longer. Just like in a pistol, when you increase recoil spring weight you slow down the action and as it moves rearward, the weapon tends to torque nose up. In other words, adding mass just makes it worse.

Contrast that to a low-mass setup with fast cycle speed which has less time to act on the weapon's position (as observed in sight picture movement).

This is also seen in AR-15s, where it's well known by the 3Gun guys that to get less sight picture movement and faster follow-up shots, you reduce the BCG mass to decrease cycle time and decrease inertia transfer.