Piston Upper Durability

[ByrdC130]

Talking with a gunsmith today and he was of the opinion that gas piston uppers aren't as durable as DI type uppers. I can't see why a piston upper would not live as long as a DI system even under heavy use. Just don't see a piston rod not living a long healthy life. What do you all think?

[68WJ]

It would probably depend more on who made the piston system rather than the fact of it being one. There are several brands with several styles of operation. Eventually one or two will rise to the top and become standard. The only durability concern I am familiar with is the buffer tube wearing from carrier tilt.

[Equalizer_2]

Agree with 68WJ and would add that certain parts COULD have more potential for breakage due to the fact there are more parts. It is just an engineering fact that more parts make a potential for something to break. Additionally there are parts to get lost if it is taken apart for maintenance.

[Clint]

The AR was not designed for an external piston.

It was designed for an internal, inline piston.

[1stmarine]

Talking with a gunsmith today and he was of the opinion that gas piston uppers aren't as durable as DI type uppers. I can't see why a piston upper would not live as long as a DI system even under heavy use. Just don't see a piston rod not living a long healthy life. What do you all think?

Everyone has an opinion and a favorite color. If he didn't give you a good reason is hard to say what he had in mind but there are piston systems out there that have completed the full service life with zero issues.
Are they always needed? no. Are they super-dependable if they are good quality from a reputable company? Absolutely

[DocGKR]

Both piston and DI designs have strengths and weaknesses. The majority of the AR15 piston conversions have failed to run reliably when looked at in aggregate. For most uses, a 16" DI AR15 will work quite well and has a long proven track record of success. Quality piston driven AR15's (HK416 is the most proven) offer some potential advantages particularly with shorter barrels and suppressed use. They also have some possible downsides--particularly looking how abruptly the bolt is forced to unlock compared to a DI AR15.

[harris hawker]

when i purchased my rifle i wanted to go with someone who built a piston system for their gun.
i looked a RRA and Stag and they had instructions on how to fit someone elses piston to their gun.
dont feel like fitting something to a gun not made for it.
i am not green when it comes to guns, but new to the ar platform.
afte alot of researching i found barrett made their piston for their gun, so that was my purchase.
now, i didnt know all the "brand name" gun makers out there when i started looking and only looked at colt, stag, RRA, then i found barrett made one and their own piston and was sold, Barrett makes the baddest freakin gun out there, they should know how to make a gun on the AR platform!!(the thought going thru my head)
now i see all the AR makers and dont regret my purchase, but wonder if i missed out in my studies of another piston\gun maker.
As an AR noob, can someone answer me this?
the DI system makes the gun crap on its own chest, right?
is the inside of the reciever all mucked up with carbon?
how is it cleaning the inside of a DI system?
i will say that cleaning the inside of a piston system is very easy, no carbonon the mechanics at all.
after watching future weapons when the HK416 came out and they shot a 100 round drum, immedatly cracked it open and pulled out the bolt and handed it to Mac, he hot potatoed it for a sec and grabbed it and looked at the camera in amazement and said "its cold"!
that he would never do that with a normal m16 after 100 rounds.

[1stmarine]

Both piston and DI designs have strengths and weaknesses. The majority of the AR15 piston conversions have failed to run reliably when looked at in aggregate. For most uses, a 16" DI AR15 will work quite well and has a long proven track record of success. Quality piston driven AR15's (HK416 is the most proven) offer some potential advantages particularly with shorter barrels and suppressed use. They also have some possible downsides--particularly looking how abruptly the bolt is forced to unlock compared to a DI AR15.

They both have their strengths and weaknesses like everything I agree. For a sustained fire type of situation the piston is hard to beat. The amount of parts and metal that is exposed to extreme heat and fouling is drastically reduced, including the bolt itself. To cash in accuracy potential the DI could be considered more accurate and lighter. That is why I use a DI in my target and hunting systems but pistons in the go-to / beat the bushes ones. With all that said it doesn't mean a piston cannot be very accurate but it has to be built with quality and certain characteristics. At the same time quality barrels and other parts are needed in the DI for top performance so there is no shortcuts if one wants performance. When I talk about pistons I mean real piston groups, not those half ass 'basement engineering' retrofits some sell. In any case I don't quite get what you mean with locking abruptly. If you test any of the top tier pistons they are very smooth. Also found the POF roller cam pin makes not just the locking but the opening of the bolt as smooth as silk. The concerns from long term carrier tilt consequences have been pretty much dissipated.
Could you please elaborate or the closing abruptly concern if you don't mind?
Thanks.

[Rob072770]

They both have their strengths and weaknesses like everything I agree. For a sustained fire type of situation the piston is hard to beat. The amount of parts and metal that is exposed to extreme heat and fouling is drastically reduced, including the bolt itself. To cash in accuracy potential the DI could be considered more accurate and lighter. That is why I use a DI in my target and hunting systems but pistons in the go-to / beat the bushes ones. With all that said it doesn't mean a piston cannot be very accurate but it has to be built with quality and certain characteristics. At the same time quality barrels and other parts are needed in the DI for top performance so there is no shortcuts if one wants performance. When I talk about pistons I mean real piston groups, not those half ass 'basement engineering' retrofits some sell. In any case I don't quite get what you mean with locking abruptly. If you test any of the top tier pistons they are very smooth. Also found the POF roller cam pin makes not just the locking but the opening of the bolt as smooth as silk. The concerns from long term carrier tilt consequences have been pretty much dissipated.Could you please elaborate or the closing abruptly concern if you don't mind? Thanks.

We both agree it is the quality of the piston system not these conversion kits but a weapon design ground up for a piston.

[LearjetMinako]

I own a Ruger SR-556/6.8, and one of the major decision of that is the piston design. The bolt carrier does stay much cleaner and cooler. Thou the piston block will recieve much of the heat and carbon. As for being more parts, barely. The bolt carrier is a solid one-piece (bolt, carrier, firing pin, retaining pin). Theres no need for gas rings. And the piston is only one piece. So far, it cycles reliable and has never missed a beat.

Both designs have their points, but each to their own.