ccw9mm

Am considering an AR-15 style rifle, but specifically want to understand the pros/cons of one specific system, at this point: the gas system.

In particular, I would like specific feedback from folks that have direct experience with either (a) a standard AR with gas-impingement operation, or (b) a variant AR with gas-piston operation, or (c) both.

To my way of thinking, dumping hot and dirty gas from the end of the barrel into the action mechanisms doesn't seem a very smart thing to do. Yeah, I know: the troops have used this for a long time. A number of companies are trying to address this one aspect of the AR's operating mechanisms.

There are alternative gas-piston systems out there, notably AR-15 class rifles by Olympic Arms with their OA platform rifles, Patriot Ordnance with their P-415/416 rifles, the Robinson Arms XCR, and the Leitner-Wise CP and SOC rifles.

Questions, for both platforms:

1. At what point during shooting does your gun dump get fouled such that it absolutely requires cleaning (if you've hit that limit)?
2. Have you ever gone 500rds without cleaning out the relevant fouled (action/chamber) areas on your gun without a failure?
3. What, if any, difference in reliability have you found in the gas-piston variant versus the standard AR-15?
4. Which would you pick and why?

For sheer sense of design and the potential for improved reliability and durability, I'm leaning toward the gas-piston variants. However, other than Olympic's system, the others are relative newbies on the market with their gas-piston systems, and I'm not too fond of being a guinea pig.

Let 'er rip.

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Hobbes

cut and paste from the other thread....

Gas operated is fine IMO. I have used it in desert and winter conditions with minimal cleaning and some harsh treatments. Not to mention harsh treatments from many Marines before me. Although carbon builds up, it self limiting because of the movement of the bolt.

I've fired about 300 rounds out of a bone dry M-16 with no problems, I've dumped multiple mags on 3 rnd burst until the bbl glowed a dull red with no problems etc....

SIXTO

I've never had an issue with eithier one, but I do tend to keep my rifles clean.

MattLarson

The most I've run at a time has been ~900 rounds at a range day with some friends. No malfunctions attributable to the gun at all (had one bad mag, which was ID'd early and removed from the pool - no other issues).

This is in a standard gas impingement design (Bushy M4A3).

IMHO, if it ain't broke, don't "fix" it. No matter how well designed, the fact is that the piston variants are all adding moving parts, some with close tolerances. That's adding more potential failures.

Matt

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Skygod

At this years Shot Show 2007 a SWAT Team was looking for a suppressor their SIG 552's. Sorry, but it uses a piston operation and will not allow a sound suppresor to function properly without causing a catastrophic failure. Just one thing to think about if your ever going to want to mount a sound suppressor.

The SWAT boys walked around with their tail between their legs when each and every suppressor manufacturer told them it's not a good idea to suppress that operating system.

Gas impingement is just fine.

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Blackeagle

That may be true for particular weapons, but it's certainly not true for piston operation in general. The Robinson Armament XCR, for example, functions fine with a suppressor. Check out the entry on their Technical Updates page or this video of an XCR with a suppressor on it.

OPFOR

The big problem, IMO, is not that the gas impingement system requires excessive cleaning to maintain reliability, it's that it is simply more difficult to clean. The "star chamber" on the AR series is notoriously hard to clean properly, and if you don't clean it properly, it can cause problems.

That being said, I have absolutely no problems with the standard gas impinged ARs from any quality manufacturer, and can tell plenty of war stories about abused, dirty, wet, frozen, et cetera M16s/M4s that have functioned flawlessly for hundreds and hundreds of rounds without being cleaned. As has been mentioned - if it were truly an unreliable system, it wouldn't be the longest serving standard long arm in the history of the US Military...

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rocky

My AR works fine. I like the ease of cleaning and access to all parts. Most rifles it would be a bigger chore to strip down .

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Redneck Repairs

IMHO the whole piston + ar action thing is another solution in search of a problem . You will just replace one set of issues with another by changing the way the system operates . Realisticly either should be fine as long as the arm is maintained but I for one would not pay a premium for one over the other , nor would i worry about which one i had .

gunmetal

http://www.defense-training.com/quips/12Jan07.html

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