Just receive my piston based M4 from POF USA! Can I say this is the best M4 I have ever had.... we ran thru 20 thirty rounds mags and 2 100 rd Beta mag dump and the gun just keep running without a hitch. did not shoot any more for my CHristmas session becasue we ran out of ammo. Here is the system I got it up. Look at the piston, opening below the front sight . it twist open and the gas piston comes out like an FAL! it is not spring loaded though.
After the shoot , I merely open up the gun and wipe the bolt carrier which is very clean and open out the piston and wirebrush a bit on the piston! do a pull thru on the barrel and the gun is as clean as anything ! cleans easier than my AK74!
Accuracy is quite good. I sight in at 100yds with british Radway green SS109 ammo and it shoot about 1" group @ 100 with the EOtech 552. I could easily ding a 6 ft gong at 400 yds with ease.
Here is the setup I had... a detachable front and flip down rear sight, Eotech 552 Rev F , grip pod and Streamlight M3 LED light.
CHeers!
Dave C!