I have been and still am searching the internet about piston AR failures but don't see many.

With CURRENT, QUALITY and FACTORY MADE (EDIT FACTORY MADE and INSTALLED) piston AR15s have there been any common failures or broken parts? Videos or blogs?

I'm not talking cheap kits but quality factory built weapons like LWRC, POF, Sig, Larue etc..

There are pictures of broken Pistons floating around.

They are not as popular ... Because it's an answer in search of a problem.



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This.... I have never seen a piston rifle break first hand but on that same hand I do not see many piston rifles.  Most all the people I shoot with went DI and only one guy I know really shoots a piston rifle and it is a LWRC M6 with low miles.

I don’t think there is enough history with piston systems to answer your question.
One of the problems is there are so many different designs and even though they may be similar that does not mean reliability is the same.

Topic Moved

I've seen a few broken ones. It's rare. Like breaking your bolt on a DI rifle rare.

my stag model 8 has been running fine for years and i shoot it a lot. its a heavy sumabitch tho

The few I have seen and heard about are almost all operator/installer error.  Pistons have been around a long time and about as refined as other major components.  
Like everything else in life, there are some cheap ones (TNW) that I wouldn't touch with a 10' pole.  We get what we pay for holds true, especially here.

100% agree. I learned the hard way. Parts are cheap made and they use DI gas key screws.
Take a look at my post. I contact their staff for support and received no return calls or emails.  
Technical staff and customer service are clueless. This is one SNAFU company!

I learned quick when it comes to guns buy once, cry once.

That's why I said FACTORY and QUALITY

They have been out for a while and I haven't heard much about problem from CURRENT QUALITY FACTORY MADE/INSTALLED piston ARs

The reason why I'm searching for failures is because I'm trying to determine which is better for me.  I have some DI and GP ARs but haven't shot the GP as much as my DI.

I really don't understand the significant downside to a GP if the parts are just as sturdy as DI.

little heavier and front heavy which isn't really that significant to me
proprietary parts (BCG and piston system) seems to be the worst thing about it. But, everyone should have a spare BCG regardless if its DI or GP.
recoil difference isn't that significant
accuracy isn't different. My CMMG gets 1.5 groups at 100 with 55gr M193 ammo

I think that with the advantages the GP is better for me since the disadvantages aren't that significant to me. I'd rather have the advantage of;
using less lube
cleaner cooler bcg
less gas in my face especially when I go suppressed
better for my 8 inch upper (SBR) with regard to cycling

Am I missing something?

No you pretty much hit all the big points.

One thing I do want to point out that isn't talked about much is recoil impulse. DI is compared to most GP rifles softer but that being said there are things you can do to mitigate recoil impulse on GP rifles from increasing your buffer weight and using a stronger spring like from wolf or superior shooting systems. Muzzle break choice will also help. Additionally different piston systems have different recoil impulses based on their design. Having owned a POF Bushmaster based system, an ADCOR, and an LWRC I will say the felt recoil impulse on my M6 IC and my POF were greater. My BEAR definitely has noticeably less recoil impulse compared to the other two but I suspect it has something to do with the longer transfer rod.

Other systems like the long stroke PWS based GP rifle's are going to also have different felt recoil impulses. As I mentioned before there are things you can do to control this. Another thing I find helps as with any rifle or shotgun is to increase the buttpad thickness.  

There are a LOT of choices when it comes to GP systems. The main thing you should worry about first is your budget. When you determine that you can really proceed as you will know whether you are looking at a drop in kit like say an Adams Arms, Osprey, ECT, or a purpose engineered GP rifle like LWRC, PWS, POF, ADCOR, Barret, RRA, ECT.

The nice thing about a drop in kit is if you don't like it you can always take it off. Kits like the Osprey allow you to do this without any need to change your gas block so long as you have a carbine length system.

I personally like GP rifles for many of the reasons you listed in addition to being left handed, the gas blowback is worse for me being as I do not and prefer not to use purpose built left handed AR's.

That being said a DI rifle with NiB or melonite internals will also serve you fine and making cleaning much easier however you will still need to fiddle with buffer weights and spring tensions if you want optimal performance.

GP rifles also tend not to care what ammo you throw in them and I've never had any issues cycling different powder loads or bullet weights. This can be remedied on a DI rifle by way of an adjustable gas block but as you know it doesn't alleviate gas blowback in your face especially if you are using an SBR and or suppressor.

Look around, ask questions, and make an informed buy and I guarantee you will be happy with your purchase.

One more thing I forgot to add if you're looking for a featherweight GP rifle Christensen Arms makes a lightweight GP rifle that solves the front end heavy rifle from what I've heard. Again it's just what I heard.

If you're looking for a balanced rifle a PWS out of the box with no modifications will be perfect for you. However that being said you can have your barrel recontoured on any GP rifle to help with balance. Even DI rifles will get front heavy when you start putting on lights, lasers, ect. Front heavy despite what many DI owners will say is NOT a bad thing. It in my opinion is how every rifle should be as it helps bring the muzzle back down faster.

I agree. The impulse or kick is slightly more. I use a heavier buffer (I think its a 5.6 oz) in my rifles and it smoothens the action and slows it down. I really don't feel like its that much of an issue. The piston is better for under powered ammo or SBRs and suppressors which makes me think its a more reliable system than DI since it will eat anything better than a DI. It being front heavy is a plus to decrease felt recoil. I don't like muzzle breaks and use FHs for my suppressors.

So, I still don't get the anger and anti GP talk when they have so much more to offer especially quality built ones. I have a Sig516, CMMG, AA (8inch) and POF piston ARs. I also have 4 DI ARs. If I were in need of an AR I would want something that doesn't need as much oil or maintenance. Even if you prefer DI you can't say the GP doesn't have the advantages above. This is not a DI vs GP thread as much. It's more of a pro piston AR and I wanted to know is I was missing something since GPs have been out for awhile now.

Because humans are stuck in their ways. It's why history repeats itself.

I can see where a lefty or people with suppressors would lean toward GP.
Although I think suppressors are fairly dirty regardless of the gas system.
The DI system is not why AR’s should be run wet, so I don’t see any benefit there.
As far as functioning goes none of my DI AR’s care about bullet weight or ammo.
My take is DI or GP is personal preference.
At this point in time DI is my preference as it does everything I need. YMMV

You aren't missing too much. The big ones are still around and some new players have come to the industry like Faxon arms for example. A lot of companies have beefed up or refined their systems in addition to focusing on different calibers. Full ambi rifles have also made some headway with the introduction of the IC line and Faxons ARAK. We've seen some innovation with new designs like the BEAR.

A lot of what I've been seeing is an increase of quality, technology employed in materials and manufacturing process's, and more variants than ever.

Now is the prime time to get into the piston game if you ask me. There is so much good stuff on the market that you can find something that will fit you're budget and needs.

The piston rifles of today are not your piston rifles of yesteryear.

It's comments like this that don't make sense to me. So, DI are much dirtier for sure. I have both and after 3 or 400 rounds the GP is much much cleaner and doesn't need oil. Also, for short barrels with short gas tubes the GP is better and more reliable. So, if it's more reliable for shorter barrels and has more direct force backward on the bcg are they not more reliable than DI?

If you completely degreased a DI and GP and shot 500 or 1000 or 2000 rounds through the without cleaning which would jam more?
I think a GP would continue to run far better especially if you use dirty under powered ammo like wolf.

Exactly what I mean. That's why I said current and quality. I don't see any need for DI with current GP and future gas piston ARs. But, I guess people are stuck in their ways and aren't open minded enough. Kind of like the 9mm vs 45 debate. I think I'll get rid of all but one of my DI uppers.

Well, there is some reasoning, to their distaste of the external gas piston.

Some view it as adding more moving parts, which are proprietary mind you, in a non-standard format. Now you require an unique bolt carrier, often an unique bolt and extra weight. Some speculate that you will end up with further bolt log wear, as there isn't as much forward pressure, as there is with the standard DI model.

With the extra moving parts, there is more to go wrong and more wear parts introduced. To boot, most will never have any issue with their DI rifles, even those made from the bottom of the barrel manufacturers. Most of us will never be in an environment in which we really will have to truly run these rifles hard.

All that said, I enjoy both.

I have not used a drop of lube on my M6 IC since I bought it. There's no need to. It has a NiB BCG and the whole rifle is ceracoated.

Guess how many malfunctions I've had with it doing this? None. Zero. Zip Zilch Nada.

I've tried that with my issued M4 once. Guess what happened? It jammed. Then it kept jamming. Then I had to go and grab some lube. After that it worked fine.

You're absolutely right. But god forbid you are. Even once. That's all it takes is that once. The one time it didn't work right and you may end up dying because of it? Sorry that's not a risk I'm willing to take. I value my life way too much to even consider allowing the possibility of that kind of risk despite how slim or maybe even unrealistic it might be.

More parts?

The piston has .... cap and piston spring, piston and sometimes a spring on the back of the bolt

DI has the key as a separate piece unlike the GP which it milled into the BC
DI has 3 rings on the back of the bolt
DI has a gas tube

might have missed something which is why I'm asking.

I agree. I was shooting an DI Colt M4 (10 inch barrel) that belonged to an 18D and it jammed because it was filthy. I actually have it on video too. And I may not be in that situation again but I still want a better rifle. You may not be in a situation where you will fire that many rounds at once but you may be in a situation where your weapon gets dirty. And to say you'll never be in that situation means nothing about the quality of a rifle. It states that the value of your life isn't that important.

Was stating moving parts sir. The piston/op rod replace a standard non-moving gas tube.

Again, not trying to slander the gas piston. My go to rifle is a LWRC IC 16'' and a LWRC Six8. But I also have a Daniel Defense that has ran like a top, no matter the abuse I pushed onto it.

I understand but was simply attempting to give the perspective that I've usually seen, from the individuals that don't care for the piston.

The excuse I'm sure we have all heard is "A solution looking for a problem".

That brings up another excellent point! The whole piston systems are more complicated than DI rifles. You loose a gas ring on a DI rifle or have a bad seal? Forget it. Your rifle now just became a bolt action rifle until you get new gas rings. In fact it's one of things I would do if I had to sabotage someone's weapons. Forget the firing pin. That can be substituted. The DI system needs gas rings to function.

A Piston rifle only needs a working piston system which if you want to get real technical about things in concept and sometimes execution, is simpler than a DI system. There are numerous possible fail points on a DI system. The DI system relies on carefully calculated gas pressures IOT operate effectively. A GP relies on mechanical force. You can't get much simpler than that IMHO.

Sure there are more parts. But no one seems to take into account how strong they are or how they are designed. It's almost to the point where it could be so fucking simple like the PWS system which is based off the AK47 (the most reliable rifle on modern battlefields) that people decide because it has more than a gas tube it is simply more prone to breakage.

Blind leading the blind.

Got it!  Also, what is the difference between the LWRC piston and Sig516? I heard they have interchangeable parts and Sig copied LWRC. What do you think about the quality of the Sig516?

From my understanding the BCG is the only thing really interchangeable. But I could in theory take an AA BCG and put it in my M6 IC with no problems.

SIG 516 Piston system:


LWRC IC Piston system:

Yes DI is a little dirtier in the upper.
Even in a carbine class with a high round expenditure I would not expect to have a problem.
There are a bunch of SBR’s out there.
I am pretty sure guys who can afford to go SBR would also be going for GP’s if they though it was significantly better.
I can run dry, which does not make it the smart thing to do.
Lubed parts equal better service life.
I am not trying to talk you out getting a piston system; I just have no compelling need for one myself.

It's not a little dirtier...its a lot dirtier! And my point about the SBRs functioning better is because there is more direct force on the BCG = more reliable.
When I say run it dry in comparison I mean to see which will fail first  which is an indication of the reliability when it does get dirtier.
I'm not concerned with ones needs... I'm concerned with having the better weapon. I'm most cases people don't shoot more than 100 yards. So, for their needs an AR in 22LR is fine. But, that's not going to be my go to gun.

After 30+ years of jams from carbon fouling and constant cleaning, from my perspective, its nice to have a system that works great, doesn't foul the receiver and is a piece of cake to clean.  

I understand that some have paid a lot of money for brand names only to learn that they paid for a stamp, and it is what it is.  But I don't understand those who have such strong opinions on things they have no experience with.  I like trying different and new things, especially since some  military specifications can be over 30 years old and outdated.

What ever you decide enjoy it and developed your own opinion based on your own experience.

S
See you're also making a critical flaw in your logic about those sbr people. You assume they even know a GP rifle exists in the first place. I've been amazed that sooo many people hell even on this site don't know they exist.

This really isn't true. There are many DI rifles that will run just fine with one ring and that isn't really even the area of a DI gun you need to be concerned about. Typically it is an extractor failure or significant carbon buildup that will cause a DI gun to malfunction. Converting the AR15 platform from DI to GP comes with it's own problems like carrier tilt and excessive force on the bolt lugs. GP's put pressure on parts that were never intended to receive abuse in the DI gun. Disclaimer: I own several GP rifles. You would be better off buying a platform that was designed as a piston gun from the ground up like the SCAR or the Tavor if you want a true piston gun without design flaws. With that said, I have a high round count LWRC M6A2 upper that is still going just fine. LMT and LWRC have addressed the GP bolt issues with stronger lugs and a better extractor. This has all been discussed on here ad nauseaum. Buy what you want but be fully informed.

GP guns will handle beta mag dumps without issue where DI guns will melt the gas tube under high rates of fire. However, you will shoot your barrel out quickly if you abuse it like this and so the DI gas tube becomes the limiting, protecting factor in this case. For the intended use of the AR, the DI system works just fine. Add a coated BCG that resists carbon build up, a mid length or longer gas system, and a enhanced extractor bolt, and you will never be able to carry enough ammo on your person to make an initially clean DI gun take a dump on you from fouling.The only real advantage of GP AR's is the BCG requires less cleaning. Oh and in your Zombie Apocalypse fantasies, they will run longer without lube or cleaning, and handle back to back Beta mag dumps with ease.

So, for SBRs and suppressors GPs aren't better?
The heat and carbon build up scratching the parts won't wear them down faster?
Can the pressure on the bolt can be lessened by a heavier buffer letting the carrier take more of the force?

The fact I state that they can go with less oil isn't for a "zombie apocalypse fantasies." It just shows that a weapon is more reliable with less maintenance. Isn't that the point and argument of AR vs AK? It also means that things other than carbon like dirt/sand are handled better in a GP since there is more direct force. Also more oil means more dirt and sand will stick to the parts. In general, it seems like all modern weapons are going toward piston systems because they are better.

I was an armorer and I have about 40 years of combined military and civilian experience with the platform.
I am saying that so you realize my opinion of DI systems has a lot of experience behind it.
I don’t see the DI system as the problem you apparently do.
What can I say, each to his own.
ETA: Google “filthy 14” if you want to see a really abused DI system.

I have thousands of rounds experience with DI here and in the military. I have see them jam in theater. I have video of me with one that jammed badly in Afghanistan.  I also have had jams at 3 gun matches using dirty under powered wolf ammo and DI ARs. Have that on video too.

The "filthy 14" has flaws. It was oiled generously and fired in a class not in the field like Afghanistan. Oiling it "generously" is the same thing as cleaning it. They are using oil to wash off the carbon. You might as well take the bolt out and hose it down with oil.

"Every round that has gone down that barrel has been fired at class, with an average of approximately 1,300 rounds every three days. It has been lubed generously with Slip 2000 Extreme Weapons Lube (EWL)."
A better test would be to fire it dry and see how long it lasts in comparison to a GP as well as AK47. And, simulate a real world environment where other factors come into play like dirt/sand.

I might be the only one but I don't want to oil my weapon "generously" in the field when my weapon gets dirty from carbon or sand.
The question isn't if a DI is a good enough weapon. The question is which is a better combat weapon.

Obviously our individual definitions of what is better are somewhat different.
Again what can I say; each to his own.

In this case, better to me means more reliable & less maintenance in real world scenarios. I understand people have their preference but that doesn't mean better. I'm pretty sure people would define a better combat rifle as one that has these qualities:

Light weight... which goes to the DI but really isn't much of a significant weight change
more rounds...same for both
accurate...same for both
ergonomics...same for both
reliable... goes to the GP
low maintenance... goes to the GP
versatile... goes to GP (better for suppressors, has adjust able gas system, not a concern in water)
good ergonomics...same for both

Am I missing something?

Jam is a pretty generic term. I can tell you that most "jams" are not due to the DI system itself but the implementation of the carbine-length gas tube. Piston systems break too and converting the AR platform comes with its own issues related to altering the design. Like I said before, piston systems designed from the ground up with a lockup designed to handle the forces involved in a GP gun are a better option although companies like LWRC, LMT and Barrett have done their best to beef up the affected conversion parts.

GP AR's will handle abusive full auto fire better than DI guns at the expense of the barrel, but again, this was not the intent of the platform.

There a lot of splitting hairs on this topic as there are multiple camps on opinions.  Some only find true mil-spec worthy and some like trying new things.  It doesn't mean anyone is right or wrong, only that different individuals have different opinions.

At first I was hesitant but after 30 years of jams and cleanings I was ready to try something different.  So far I don't regret it.  Does it mean its the best, absolutely not.  Does it mean its the best for me, absolutely.

So the moral of the story is to gather all the information you can and make the best judgement call for you.

This is what I'm doing. And, thanks to all for their input. I was trying to see if my ideas and facts about pistons are true.

I have 223 suppressors and SBR AR15s. For me, I can't see any reason why I would have anything other than a modern quality factory assembled piston AR15.