I've changed my opinion on piston driven rifles.

[ChattanoogaPhil]

I weighed the +/- of converting to a piston system and dismissed the idea. However, I did install an adjustable gas block. Significant difference in the operation of the rifle and my shooting. Big +.

 

[jdh]

It's absolutely true.

Not it is not.

Hot dirty combustion gasses are redirected into the action to act against the bolt/carrier to cycle the action.

Watch a slow motion video of the right side of an AR being fired. See that big puff of smoke coming out of the ejection port? That is your hot dirty gasses being vented from the action by way of the two holes in the side of the bolt carrier and out of the action through the ejection port.

Side note: If you're getting excessive build up in the bolt carrier perhaps you should try better quality ammunition or a cleaner burning powder in your reloads.

 

[Tbat]

I have a few direct impingement ar15's and I have finally ventured into piston AR's with the purchase of a 16 inch Huldra 5.45x39 piston upper M4 barrel profile(basically an Adams Arms piston system) a while back.

I don't believe that the argument that piston setups are heavier than direct gas impingement rifles/carbines is that valid any more, of course it may depend on the particular manufacturer. This Huldra upper subjectively feels no heavier than my direct impingement uppers, including my Smith & Wesson MP15A and MP15 OR rifles.

Additionally, I have a friend that recently got a LWRC upper with the spiral cut heavy barrel and surprisingly it was really well balanced and did not feel as heavy or any heavier than my my direct impingement Rock River upper with a heavy profile barrel.

I don't know why we can't like both, piston and direct gas systems. I know I like both. I guess time will tell, if the longevity of the piston system will match that of the direct gas impingement system.

 

[sgtsandman]

I have no preference with either system myself. I have firearms with both. Weight would depend on the design. With the extra metal in the piston system from the piston and the operating rod, it would have to be at least a little heavier but I'm sure that can be compensated for in other ways like a lighter barrel. I like both and don't have any issues with getting a firearm with either system.


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[vmumford]

With all due respect...the FACT that the DI version of the M-16 is still around and in ACTIVE service some 50 years AFTER introduction speaks VOLUMES for the "platform."
I personally CARRIED an M-16 into combat in 1978 and it NEVER...NOT ONCE, NOT EVER, NEVER, NEVER, NEVER, failed to chamer, fire, extract, eject, and RE-chamber for me!

I carried that ******* up and down the mountainous rain forests of Panama and it NEVER failed...NEVER! I'm not quite sure exactly what a "gas piston" system can bring to the table to make me think IT is the proverbial "Cat's Meow!"

Today I own a "rack" of AR type rifles, all DI, and ALL have worked 100%

Just saying...for the sake of those who buy the AR-15, "as is" and don't necessarily want to drop $300+ into a piston conversion!

For all those who have shelled out CASH for a "Mil-Spec" operation AR-15....YOU'RE perfectly FINE with the DI system!!!!

Thank you for your service and I agree. No need to change if it has DI. I have both and both work well.