Are piston ARs reliable and durable?

[checkmyswag]

I've read about the tilt problem wearing on them.

Has this been solved? Which makers are putting out good piston ARs? What's a good value in piston ARs?

Yes...I like the DI guns too. Used those in the military and never had major problems but I never ran them hard either.

[tahunua001]

I've never run a DI Ar hard enough to warrant a piston. military pistons may be a good idea for military where you may be using it for a long period of time without cleaning but civilians have little to no need for one. if your gun is so dirty that it begins to malfunction then you should probably either give it some more lube or learn to clean it ever couple thousand rounds.

when it comes to civilian use the piston can be a hindrance more than a help because they require a specific pressure to operate. military users have only a couple rounds to choose from and those are pretty close to eachother pressurewise so odds of them having pressure issues with their piston system is small and almost a no brainer but for civilians we have literally hundreds of different kinds of amm0 and each one generates different pressures. gun companies compensate by making their pistons adjustable to compensate but that also means that you either have to start keeping a log book of of all the ammo you have shot and which setting to use that performs best or you have to make a number of test shots every time you change ammo to find out what setting cycles the best.

now the rest of the thread is going to be ignoring my comments and all of the mall ninjas explaining why it is necessary for every person that owns an ARto add one of these $600 malfunction magnets to their existing setup nad why the existing stoner design that still functions well enough for 10 million shooters is antiquated and unreliable.

[Jo6pak]

Oh Moses small the roses, here we go again.

Let's please help the OP anser his question. That question is NOT "Is a piston driven AR worth the money?"
Please re-read the question asked.

If you would like to debate the merits/shortfalls of DI and Piston, please find one of about 1000 threads discussing it.

now the rest of the thread is going to be ignoring my comments and all of the mall ninjas will jump up and chase their tails in a never-ending bickerfest of meaningless drivel.

[checkmyswag]

Correct, 100% not doing a "vs" thread, but tahunua001 brought up some good points.

Just want to know the facts.

Has carrier tilt been solved and/or which are good piston models? Are they at least as reliable and durable as a DI AR?

I am also looking at DI models such as the Colt 6290, RRA Elite Operator and Windham Weaponry.

But, as has been noted, this is NOT a DI vs piston thread. I've read enough of those to cause me to start this separate thread.

[HKGuns]

"Generally" speaking, the conversions will be the most problematic. A piston rifle that was designed to be a piston rifle will work just fine. There are lots of well designed piston rifles that work as well or better than their DI counterparts, depending on your intended use.

[checkmyswag]

HKguns, have any recommendations? Can I get away with going $1500 or less for a piston gun?

[impalacustom]

Not going to get into a vs either, but mine has over 6,000 rounds through it and works great. Yes I either shoot 55gr or 62gr surplus though, nothing else has been in it. Carrier tilt isn't a problem here, maybe I'm lucky I don't know. Rifle runs great and has never had issues.

[oneshot onekill]

I think it's important to understand what exactly is going on with regard to "Carrier tilt"...
Gas escapes thru the port under the front sight or gas-block. It drives a piston located right there near the front of the rifle. The piston pushes a rod along the top of the barrel and into the front of the upper receiver. The rod strikes the Carrier Key located on top of the BCG near the front of the BCG. Because all of the energy is absorbed right there at the top of the BCG (off axis), the BCG lifts upward as well as being driven back. as the front of the BCG is driven up, physics dictates that the back of the BCG is driven down. In early AR piston systems the back of the BCG was left alone by the manufacturers. Because the back of the BCG was basically straight and flat, it could chisel away the inside bottom of the buffer tube. This could cause the buffer retaining pin to pop out upon disassembly (which really is no big deal except that it freaks out beginner AR users). THAT'S CARRIER TILT.

In most cases the damage was minimal and would cease after a certain point and cause no more issues. Although I've heard of it, I have never seen carrier tilt cause a failure in any AR (and I've shot thousands of rounds thru AR's that displayed major carrier tilt wear). A major contributor to the problem was the BCG-to-upper fit. If the tolerances were loose the BCG could move up and down more and cause more of a problem. That's why some AR's would have more wear than others. Even among the same brand.

In later AR piston systems they fixed the problem by including a BCG with the system which was designed slightly different in the back as well as having a solid carrier key area machined-in as part of the BCG.

Hope that helps. Please feel free to ask me more about this as I spent several years and tens-of-thousands of rounds studying these systems.

There were also other issues, some legitimate, some not so much, but I don't want to write a book here so I'll stick to your original question.

As far as brands go, my favorite Piston AR is a POF. Those guys have really done a great job addressing the issues and building a Piston AR pretty much from the ground up. They are pricey though.

I also have to say that I am in now way saying that Piston AR's are better than DI... Just different. Both systems have their issues.

[Crow Hunter]

Pistons are not a panacea. They are a compromise that has certain advantages/disadvantages different than those of a DI which is also a compromise with certain advantages/disadvantages.

Carrier tilt can be mitigated. Most of the major factory delivered rifles seem to have done something to mitigate it. (LWRC, LMT, HK, Ruger).

That being said.

There isn't alot of data out there on long term usage available for civilian consumption. Particularly relating to the effects of the non axial loading on the bolt lugs/cam pin. (Those parts were dimensioned around a in-line force)

The HK (Military) and the LWRC (DEA) have had the most usage, but no one is talking about their results publicly. (If you research in the right places you get about as many negative comments as you do positive from high volume users. There are very specific problems for both.)

When you add a piston to the AR, you are adding additional parts that could be a failure point. Those parts are most likely proprietary parts, only available from that specific company. So make sure you pick a company that you feel will be around to support it with parts/upgrades in the future.

You lose the ability to buy replacement parts, upgrade parts, and interchangeability with the current standard military and police long arm. If you are willing to live with those options to reduce the cleaning/lubricating requirements of your BCG or use a really short barrel then go for it. (If you are planning on using a suppressor, the DI system is quite a bit quieter for the same barrel length due to the longer distance to the gas exhaust port)

The good thing about the M16FOW, however, is that you can usually change back by just swapping uppers if you change your mind later.

[Skadoosh]

Can those BCGs designed for the piston system still be used if the rest if the upper was switched back to a DI operation?

[tulsamal]

I have several AR's and like them all. I also have a Ruger SR556 and like it a lot. I'll grant you I haven't taken it into heavy field conditions and abused the crap out of it but my general civilian use has been very positive. Rugged and well made. Easy to take apart and clean. I like it a lot. (And I haven't seen any evidence of carrier tilt.)

Gregg

[BPowderkeg]

Are piston ARs reliable and durable?

I've read about the tilt problem wearing on them.

Has this been solved? (carrier tilt is way over rated, i own several piston AR's from two different makers, i see no problem in mine, one of them, 8 y.o., has close to 10,000 rounds thru it)

Which makers are putting out good piston ARs? (i am a little prejudiced, BUT, LWRCI is a very good one and is one of the first to go all piston, due to the innovator, Paul Leitner-Wise's invention, after he first put them out, every gun maker had to copy the idea with slight changes to avert copyright infringement. Paul now has a new company that makes the MOD-1, i have one of them, there is absolutely NO evidence of carrier tilt after 3,000+ rounds )

What's a good value in piston ARs? (any where from around $1800.00 to $3500.00)

Yes...I like the DI guns too. Used those in the military and never had major problems but I never ran them hard either.

i too have a few DI carbines, mostly Colt, love'em all, if i ever sold one my wife would shoot me with her own AR-15 ........

[Crow Hunter]

Can those BCGs designed for the piston system still be used if the rest if the upper was switched back to a DI operation?

Depends on the design, but usually no.

Most of the newer designs have a solid strike face machined into the BCG in place of the bolted on hollow DI part.

The bolts could be used if they have a place on them for gas rings, otherwise, they can't be used. (HK does not, I think LWRC can be, LMT can be)

You are really better off just swapping the complete upper assembly. The lowers should be interchangeable.

The biggest risk with piston AR designs are two fold:

1. They don't have the 50 years of use and millions of rifles in service with millions of rounds fired that the DI system has to know what kinks there are and what might need to be changed over time and when. With the exception of the HK 416, all the other rifles are just civilian rifles. Even the HK 416 has only been produced in very limited numbers for the US and Norway. (Google Norwegian HK 416 problems)

2. There is no common design. The company you choose may go under or decide to change the design and no longer support your version.


If a person is willing to take a chance with that, pistons have some advantages for very short barrels, changing barrel lengths, over the beach operations & lubing/cleaning frequency/location.

[BPowderkeg]

The bolts could be used if they have a place on them for gas rings, otherwise, they can't be used. (HK does not, I think LWRC can be, LMT can be)

yes, LWRCI uses a gas ring bolt, as do most AR-15/M16/M4 assemblers, there are very few actual manufacturers of the afore mentioned firearms from the very smallest part to the barrel, BCG, upper & lower receivers, stocks, hand guards, quad rails, etc.

Can those BCGs designed for the piston system still be used if the rest if the upper was switched back to a DI operation?

Depends on the design, but usually no.

yes, depends some piston carriers used a gas carrier, removed the gas key, replaced it with a solid key with a dimple in the striker end, as long as the key dove tail has not been modified or the screw holes not tampered with the carrier can be converted back to gas DI.., BUT !! ya gotta know peanuts from peanutbutter not every assembler does the same when making modifications, as well as not every gun owner lives in -40 degree F. climate 8 months out of the year.

here is the lowdown:

Select Fire: HK416 (5.56 NATO)

Civilian Semi: MR556 (5.56 NATO)

the HK416 can only be had by Military & Police

Mr.Crow Hunter is correct in his observations and i concur.

[robertsig]

I've read very good things about the PWS Piston AR's.

[rbernie]

http://thefiringline.com/forums/showthread.php?t=492629

[buckhorn_cortez]

If you're interested in a piston AR, then I would look carefully at the Barrett REC7. The gun is designed as a piston rifle. The bolt/carrier are Barrett's design and for Barrett's piston system. The bolt has no gas ring, and the carrier has an integrated striker face as part of the design.

There is no carrier tilt in the Barrett because of the bolt / carrier / piston design. The bolt/carrier will only work in the Barrett upper and a standard AR bolt will not work in a Barrett upper.

The piston system weighs 3.5 ounces and can be removed from the rifle by rotating a small lever at the front of the gas block and removing the gas plug. After that, you tilt the gun barrel down, and the piston and rod will drop out of the rifle.

You can find them for around $1770.

[robertsig]

I just read about the Barrett and it is a short stroke piston design. How is their design any different than POF, LWRC, Adams, etc?

[buckhorn_cortez]

I just read about the Barrett and it is a short stroke piston design. How is their design any different than POF, LWRC, Adams, etc?

That's a lengthy answer to a short question. The Barrett bolt is totally different than a standard AR bolt. It has no gas ports in it, no gas ring, etc. The piston drive is as close to the outer surface of the bolt as you can get it. The carrier is made so that it cannot tilt in the receiver. The rifle is NOT a DI AR adapted to be piston drive.

The piston chamber vents out the front of the gas block - in effect, it's self cleaning and self regulating. The literature and instructions list the gas plug as being "two position" - and it's not clear in either what that means "open / closed" or? When you operate the gas plug you find that there is a detent between closed and open that is to be used if the rifle is equipped with a supressor and increases the venting slightly. When viewed from the front,
there is a locking detent fully closed at 9:00, another detent stop at 11:00 and then open at 2:00 (no detent - plug pulls out).

After 2,000 rounds, I pulled the piston out to see what it looked like, and it had very little fouling on it and when wiped with a "carbon killer" type cleaner, left very little residue on the cleaning rag. The same for the inside of the piston chamber. The pieces are nitride treated so the surfaces are very hard.

The barrel is chrome lined, the bolt group is NP3 treated, the piston system is nitride treated.

Barrett manufacturers all of the parts with the exception of the furniture (rails, grip, stock, etc.) and barrel. Barrett has always contracted the barrels for their rifles and they are usually made by Federson, Krieger, or Obermeyer to Barrett's specifications.

The rifle is finely fitted, very tight, and nicely finished with no tooling marks. My only complaint would be the trigger. They are "combat rifles" in the sense that the trigger is made to be used under conditions where it could get snagged etc. and the pull was 6.3 pounds with a longish reset.

I dropped a Wilson Combat TTU-3G trigger in mine and changed the charging handle to a MechArmor TacOps 1 as I have a scope on the rifle and wanted to access the charging handle without having to reach under the scope.

A point-by-point comparison to each of the rifles you listed would take pages. When I purchased the REC7 I looked at the POF and Adams system at a local gun shop and field stripped the guns to see how the piston worked with the bolt. Neither were engineered as well as the Barrett in my opinion. No dealer in my area stocks LWRC so I cannot comment on their rifle.

[5RWill]

Originally Posted by HKguns

"Generally" speaking, the conversions will be the most problematic. A piston rifle that was designed to be a piston rifle will work just fine.

Here's your answer.

FWIW a system built ground up on the piston/AR design, not a conversion, will get expensive.

[chadio]

I don't know, give them another 10 or 20 years ... then we will know something.

[robertsig]

There are designs that were flawless from day one, and they are designs which took time to mature (cough...AR15...cough). There is no reason to believe that a well built and fully functional piston AR can't fall into the first category. This 'battle-proven' term I keep hearing is crap. There are a lot of fine designs that were never in a War, just like there were a lot of crappy designs that were IN wars.

Many guns are designed or built based on what was learned from before. Don't assume that a piston AR takes its' roots back to the 1960's Vietnam era. It takes it from what is known of AR's in 2012.

[Rogervzv]

The Ruger SR556 was designed with the earlier issues in mind. This is a proven and robust design which does not appear to have any maintenance issues. DI versus piston involves various trade offs and either system can be good. I love the ease of cleaning of the piston system on my Ruger. Nothing against DI guns which I have shot for a lot of years also.

The piston system on the Ruger SR556 is very smooth and promotes very nice accuracy. Can't say enough good things about how easy the rifle is to clean.

[Crow Hunter]

There are designs that were flawless from day one, and they are designs which took time to mature (cough...AR15...cough). There is no reason to believe that a well built and fully functional piston AR can't fall into the first category. This 'battle-proven' term I keep hearing is crap. There are a lot of fine designs that were never in a War, just like there were a lot of crappy designs that were IN wars.

Many guns are designed or built based on what was learned from before. Don't assume that a piston AR takes its' roots back to the 1960's Vietnam era. It takes it from what is known of AR's in 2012.

Which designs have been "flawless from day one?" I don't know of any.

Designs without any battlefield pedigree should be considered suspect. I do testing for a living. There is no way to develop a test that can simulate real world conditions. Things that work well in testing/lab can and will fail in use.

Just because something is based on things that have worked before, doesn't mean that the combination of design features will work. Look up HK416 problems, particularly in Norway which has a much wider distribution and usage history of this rifle than other countries.

Rifles that have been issued and used in wide scale combat operations and updated/modified to correct issues found have a much more reliable pedigree than a rifle that has no such "testing" under it's belt.

How do you know that a rifle design that has never seen combat will perform in combat? How do you know that it is a "fine design" of a combat rifle if no one has ever used it in combat?

[Nanuk]

Piston Ar's = Solution to a non existent problem.