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Page AR-15 » AR Piston Systems
AR Sponsor: bravocompany
Posted: 12/27/2011 10:56:25 AM EDT
I always hear from the DI crowd that "its just another part that can fail."
I think most of them that say this never had experience with GPs and just say it becaus they dont have one or experience with one.

So, does anyone have experience or a youtube video that has something about a QUALITY FACTORY piston (LMT, LWRC, AA, CMMG) failure?

I have looked and couldnt find anything.

I have a CMMG GP but only put 1k to 1.5k through it.



EDIT failing meaning broken parts not a stove pipe or minor issue that may occur in DI gins

for example, the piston rod breaking

also I'm talking about current model designs like curent LMT, CMMG, AA or LWRC.
Link Posted: 12/27/2011 12:27:18 PM EDT
[#1]
What do you consider failing???
Would this qualify.



Would an LWRC that broke one of the gas key screws be a failure (i know it's the old design but they sold them).

Would an lwrc that got enough sand/fine gravel in it to lock the bcg up in the receiver extension be a failure?

Everything man made will break ,malfunction or fail at some time.
The real question is the gas piston system more reliable or more durable in the long run.
I'm not convinced from what i've seen.

Link Posted: 12/27/2011 12:39:07 PM EDT
[#2]
It doesn't matter whether it's piston or DI, they both can fail, and have both failed due to various reasons.
Link Posted: 12/27/2011 12:53:45 PM EDT
[#3]
I don't believe from both my experience and what I have read here and other forums that "quality" pistons or DI guns have major failures very often.

That said you can be one of the unlucky to get a bad gun but on that rare occasion it will likely be replaced or fixed to your satisfaction.

What i have seen more problems with are cheaper guns or put together guns that never seem to run well enough to trust them.

Buy a good quality one.
If you can't afford a $2500.00 LWRC or $1500.00 PWS buy an $800.00 DI Rock River or Bushmaster. They are great guns and will serve you well.

If ever there was a year to be better prepared just in case it would be 2012 or so some Mayan said


Wulfmann
Link Posted: 12/27/2011 1:54:54 PM EDT
[#4]
Isn't this kind of a "loaded" question.
Link Posted: 12/27/2011 2:42:19 PM EDT
[#5]
so with the advantages of piston systems and being durable why would anyone take a DI over GP?

I was sold on a GP when I got my CMMG and found out how clean my bcg was in comparison to my 4 other DI ARs.

I just wonder why all the GP bashing occurs if they are reliable and more advantages than DI. Is it because most people never tried it or have experience with it?



Link Posted: 12/27/2011 4:41:34 PM EDT
[#6]
EDIT failing meaning broken parts not a stove pipe or minor issue that may occur in DI gins

for example, the piston rod breaking

also I'm talking about current model designs like curent LMT, CMMG, AA or LWRC.


Not a minor issue when the rifle won't make it through one mag without malfunctioning


Quoted:
so with the advantages of piston systems and being durable why would anyone take a DI over GP?

I was sold on a GP when I got my CMMG and found out how clean my bcg was in comparison to my 4 other DI ARs.

I just wonder why all the GP bashing occurs if they are reliable and more advantages than DI. Is it because most people never tried it or have experience with it?




I'm waiting on real evidence of something besides run cleaner.
I can see someone with a supressor wanting one for high round count sessions.

I'm not bashing piston ar's i'm just not convinced they are "better" or more reliable. It's more like another way to skin a cat.
That POF i posted a picture of is a real pleasure to shoot when it would string a few rounds together without malfunctioning.

The LWRC i saw jam up with sand was a current mdl.
Up untill that happend the rifle ran great but it didn't seem to prove "more reliable"
Seemed more like on par with any other quality ar.
Link Posted: 12/27/2011 5:12:07 PM EDT
[#7]
Quoted:
EDIT failing meaning broken parts not a stove pipe or minor issue that may occur in DI gins

for example, the piston rod breaking

also I'm talking about current model designs like curent LMT, CMMG, AA or LWRC.


Not a minor issue when the rifle won't make it through one mag without malfunctioning


Quoted:
so with the advantages of piston systems and being durable why would anyone take a DI over GP?

I was sold on a GP when I got my CMMG and found out how clean my bcg was in comparison to my 4 other DI ARs.

I just wonder why all the GP bashing occurs if they are reliable and more advantages than DI. Is it because most people never tried it or have experience with it?




I'm waiting on real evidence of something besides run cleaner.
I can see someone with a supressor wanting one for high round count sessions.

I'm not bashing piston ar's i'm just not convinced they are "better" or more reliable. It's more like another way to skin a cat.
That POF i posted a picture of is a real pleasure to shoot when it would string a few rounds together without malfunctioning.

The LWRC i saw jam up with sand was a current mdl.
Up untill that happend the rifle ran great but it didn't seem to prove "more reliable"
Seemed more like on par with any other quality ar.


so if it doesnt malfunction more or less than DI is still has the advantage with SBRs, suppressors, water and less oil needed.

SBRs the piston system is more effective and you dont need muzzle devices to increase blow back
suppressors ... less gas in your face
cleaner bcg = less oil needed
in and out of water (shooting out ouf water but right after you come out of water) - dont need to drain the gas tube

if reliability is the same why wouldnt it be a better system with the above advantaes? is my thinking wrong?
Link Posted: 12/27/2011 6:59:32 PM EDT
[#8]
I seem to remember an instance (posted in this forum) of an Adams Arms piston rod suffering a catastrophic failure.  Anyone remember that?  It's the first and only example I can think of.
Link Posted: 12/27/2011 7:02:11 PM EDT
[#9]
Quoted:
I seem to remember an instance (posted in this forum) of an Adams Arms piston rod suffering a catastrophic failure.  Anyone remember that?  It's the first and only example I can think of.


was it factory assembled

seems like its rare
Link Posted: 12/27/2011 9:31:00 PM EDT
[#10]
Someone is
Link Posted: 12/28/2011 4:34:48 AM EDT
[#11]
Quoted:
Quoted:
I seem to remember an instance (posted in this forum) of an Adams Arms piston rod suffering a catastrophic failure.  Anyone remember that?  It's the first and only example I can think of.


was it factory assembled

seems like its rare


I forget all the details and honestly I could be off the mark.  It IS rare.... REALLY rare.  However, if you build enough of something you're bound to get at least one problem sometime.
Link Posted: 12/28/2011 4:55:25 AM EDT
[#12]
Quoted:
so with the advantages of piston systems and being durable why would anyone take a DI over GP?

I was sold on a GP when I got my CMMG and found out how clean my bcg was in comparison to my 4 other DI ARs.

I just wonder why all the GP bashing occurs if they are reliable and more advantages than DI. Is it because most people never tried it or have experience with it?





You're making a large assumption (GP > DI). In my experience with both, they work so why pay the premium for GP. In addition, the DI guns seemed to be more accurate and are made from, standard parts. There is no GP standard so you're married to the manufacturer you chose. This question has been asked a million times and there isn't a clear winner.

As far as failures go, the AWG had barrel extension locking lugs crack on Hk 416s due to BCG tilt

Link Posted: 12/28/2011 4:56:53 AM EDT
[#13]
A quote from this thread.  http://www.ar15.com/forums/t_3_126/555809_Carrier_tilt_buffers.html&page=1

Quoted:

Me personally? No, I do not have proof, but people have posted pictures of BCGs that were wearing down. Again on most well made systems this is a non issue so why go adding shit that does nothing to fix anything.



I'll vouch for Slash's buffers.   I've got the H3 buffer.   Cycles all ammo ranging from TulAmmo to Hornaday 75gr TAP. Buffer works exactly as advertised.   No unusual BCG wear.   Keeps carrier tilt to a minimum.   The only tradeoff is that you have to pop the front and rear pins out when cleaning.  Not a big deal to me.  I find it hard to believe when I see a picture posted of a particular piston system that has had "thousands of rounds" through it with no signs of carrier tilt.  I shoot with guys with high round count POFs and LWRCs .   Both guns have very visible carrier tilt.  

After thousands of rounds, the stock buffer tube on my LMT MRP catastrophically failed.    Spit the buffer retaining pin out while firing and locked up my gun.  

https://lh6.googleusercontent.com/-F56qGW27nPc/TpHouSIv5iI/AAAAAAAAAH0/bE8qwJeblsU/s400/IMG_20111009_132502.jpg

Here's my tube after installing Slash's buffer.   There is a tiny bit surface wear, but it gotten  any worse in 1000+ rounds.  

https://lh4.googleusercontent.com/-Ey4kyISqbBE/TpHpcOlSFmI/AAAAAAAAAH4/ZBWnYQH_Qjk/s400/IMG_20111009_132747.jpg

Link Posted: 12/28/2011 2:00:41 PM EDT
[#14]
Quoted:
A quote from this thread.  http://www.ar15.com/forums/t_3_126/555809_Carrier_tilt_buffers.html&page=1

Quoted:

Me personally? No, I do not have proof, but people have posted pictures of BCGs that were wearing down. Again on most well made systems this is a non issue so why go adding shit that does nothing to fix anything.



I'll vouch for Slash's buffers.   I've got the H3 buffer.   Cycles all ammo ranging from TulAmmo to Hornaday 75gr TAP. Buffer works exactly as advertised.   No unusual BCG wear.   Keeps carrier tilt to a minimum.   The only tradeoff is that you have to pop the front and rear pins out when cleaning.  Not a big deal to me.  I find it hard to believe when I see a picture posted of a particular piston system that has had "thousands of rounds" through it with no signs of carrier tilt.  I shoot with guys with high round count POFs and LWRCs .   Both guns have very visible carrier tilt.  

After thousands of rounds, the stock buffer tube on my LMT MRP catastrophically failed.    Spit the buffer retaining pin out while firing and locked up my gun.  

https://lh6.googleusercontent.com/-F56qGW27nPc/TpHouSIv5iI/AAAAAAAAAH0/bE8qwJeblsU/s400/IMG_20111009_132502.jpg

Here's my tube after installing Slash's buffer.   There is a tiny bit surface wear, but it gotten  any worse in 1000+ rounds.  

https://lh4.googleusercontent.com/-Ey4kyISqbBE/TpHpcOlSFmI/AAAAAAAAAH4/ZBWnYQH_Qjk/s400/IMG_20111009_132747.jpg



these were problems when they first came out werent they?
that problem with carrier tilt were fixed

I understand that you dont have standard parts but if you didnt have access to parts and may need them you can always carry a spare bolt carrier, piston and gas block. Of in the case of LMT and replacement barrel with gas block.

My question still isnt answered...if newer GP systems have the advantages listed above and are just as reliable why not take a piston over a DI?  

I guess youre saying accuracy and parts availability.  Well maybe accuracy might be affected a little but GP is still accurate enough for a combat weapon. As far as parts availability a bolt carrier, piston and gas block dont take up much space.

So it it correct to say... if you want accuracy and parts availbility go for DI. If you want to run your weapon with out having to oil it or in and out of water or running a suppressor or have a SBR go for a GP. Is this correct?

If so, GP is the answer for SBRs or less maintenance (oil)
Suppressors +/- ... could go with either but GP might be a little better with less gas in your face
If you want pure accuracy the answer is DI

I just want to see if my thinking is correct
Link Posted: 12/28/2011 2:05:01 PM EDT
[#15]
If made properly i don't see how piston parts would fail at any higher rate than any other non-ar15 piston gun out there.  Granted ar15 piston kits are all retro fit style systems so the rods are probably thinner and the piston parts may be smaller than other style guns. If installed properly i don't see how they would fail from poor design?  If the system lasts as long as the barrel, i think that's a reasonable expectation, but eventually everything fails at some point.

Hearing of failures of either DI or Gp you have to also question faulty installation, or an overgassed barrel port hole etc....  If you install the system and the rod doesn't move freely, it could break after a few hundred cycles.  Or if it's overgassed and you compensate with a super heavy spring, you are adding much more force then it was designed for.
Link Posted: 12/28/2011 2:19:04 PM EDT
[#16]
I guess a good weapon system would be an LMP MRP with 2 barrel systems

One GP barrel in 10 or 16 inch for all around combat and one DI 18 or 20 inch for accuracy.
Link Posted: 12/28/2011 3:48:35 PM EDT
[#17]
Both GP and DI systems are good to have.  Both have their pros and cons. If I was running a sound reduction device, I would go with the GP. Anything else: DI. Now, you are asking qualitiy and durablity of parts said. I will give you answer when I run 10K rounds of munitions. Parts are parts, if the part is well made, it will last a long time. To me, parts can fail when you lest expect it. I would rather stock on the small or unique parts than worry about for when at what round count did that part failed.
Link Posted: 12/28/2011 4:35:17 PM EDT
[#18]
I'll just add as far as accuracy is concerned that my LWRC M6A2 will shoot .75 inch groups when I do my part. So I would say DI guns are not MORE accurate
Link Posted: 12/28/2011 4:47:54 PM EDT
[#19]
What ammo did you use when you got the 3/4moa grouping?
Link Posted: 12/28/2011 5:02:53 PM EDT
[#20]
Link Posted: 12/28/2011 5:04:52 PM EDT
[#21]
I got just under 1 MOA consitantly using Barnes 70gr. TSX handloads out of my PWS MK116 last weekend.  I was impressed... I've NEVER gotten Barnes slugs to shoot that well for me before.  Glass was a Pride Fowler 3X9.

What's more impressive was that I was getting 1.5-2.0 MOA using 1972 LC M193 ball.
Link Posted: 12/28/2011 5:07:43 PM EDT
[#22]
Quoted:
Both GP and DI systems are good to have.  Both have their pros and cons. If I was running a sound reduction device, I would go with the GP. Anything else: DI. Now, you are asking qualitiy and durablity of parts said. I will give you answer when I run 10K rounds of munitions. Parts are parts, if the part is well made, it will last a long time. To me, parts can fail when you lest expect it. I would rather stock on the small or unique parts than worry about for when at what round count did that part failed.


so for a SRB of 7 or 10 inches you would still want a DI?
Link Posted: 12/28/2011 5:34:35 PM EDT
[#23]
There is no GP standard so you're married to the manufacturer you chose
.
that's the only real downside I've seen so far. I have a CMMG system and it has been very reliable. Parts from the manufacter are avialable with ease. with all parts of possible breakage or wear items being fairly easy to replace. CMMG says thier return spring should be replaced at 7500 rds. (its a $1.25 part on thier site), I would say you would be replacing your Bolt at that point too, but that's for DI or GP in my opinion.
My gun stays much cleaner than my other DI i had
I wish I had 1000 CMMG's and the Ammo to run them to death and see for you... but $$$ ain't there for the test.
Link Posted: 12/28/2011 6:39:52 PM EDT
[#24]
Quoted:
Quoted:
Both GP and DI systems are good to have.  Both have their pros and cons. If I was running a sound reduction device, I would go with the GP. Anything else: DI. Now, you are asking qualitiy and durablity of parts said. I will give you answer when I run 10K rounds of munitions. Parts are parts, if the part is well made, it will last a long time. To me, parts can fail when you lest expect it. I would rather stock on the small or unique parts than worry about for when at what round count did that part failed.


so for a SRB of 7 or 10 inches you would still want a DI?


For a SBR running a 7 or 7.5  barrel is pushing it for a DI system IMO, I have seen the 7" uppers work and fail for various problems. I have shoot DI 10 and 11.5 barrels setups without any problems.  The reason why I would have a GP system is for a future option that I want to explore ie a sound suppressor.  Having a sound suppressor on a DI is fine with me.  You need take it into consideration that a suppressor runs a DI dirtier. The GP, I have options for running normally or going really quiet with a suppressor.  I do not believe there is an all mighty cure all for the which is better for an AR.  You need to know the limits and how close you can get to it without exceeding it.
Link Posted: 12/29/2011 2:38:46 AM EDT
[#25]
Greetings.
I could not find an introductions thread so Im jumpin in as is.

I live in South Africa.

We struggle to get American AR15s into the country. (something to do with your export laws)

Thus we are forced to switch to European Piston AR15s and there has been at least 1 complaint of the V-AR resulting in double feeds, FTEs and the buffer actually breaking.

This fellow complained on www.gunsite.co.za

The V-AR piston AR15 type rifle is found here :   The V-AR

Ps: Could not think of a normal Board name
Link Posted: 12/29/2011 5:24:04 AM EDT
[#26]
Quoted:
Greetings.
I could not find an introductions thread so Im jumpin in as is.

I live in South Africa.

We struggle to get American AR15s into the country. (something to do with your export laws)

Thus we are forced to switch to European Piston AR15s and there has been at least 1 complaint of the V-AR resulting in double feeds, FTEs and the buffer actually breaking.

This fellow complained on www.gunsite.co.za

The V-AR piston AR15 type rifle is found here :   The V-AR

Ps: Could not think of a normal Board name


Looks cool, what's the price of that thing converted to USD?

Link Posted: 12/29/2011 7:47:48 PM EDT
[#27]
for what i have learned over the years ,most of the time when things fail is when Q/C fails and poor quality of  materials are used ,owner poor care /neglect ...or a mix of all or part of all named !
Link Posted: 1/8/2012 3:50:52 AM EDT
[#28]
Im sure many of you have seen this POF video on DI vs GP but for those of you who have not, it seems to do a decent job explaining SOME of the differences and issues with SBRs etc.

POF Video

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