It is funny how things change over time.
The piston AR in the world of real high speed low drag was intended to make Short Barreled Rifles (SBRs) with suppressors reliable before we understood how to make SBRs with Suppressors reliable with the DI system.
Now days the guys in the know understand how to make the DI system work better than any piston in the first 2000 rounds or so without any cleaning or maintenance.
Larry Vickers was an early proponent of the piston upper, even he has poste on his site that it probably only is off benefit to someone who has to be able to do sustained full auto fire.
We has 11.5in Bushmasters in Iraq in 05 that gave problems initially and Bushmaster got us different buffers and buffer springs and the guns ran great after that.
Give me a shovel and some nice dirt or sand and I can stop a piston gun sooner than a well built DI gun in the first 2000 rounds from a good cleaning and lubing.
After 2000 rounds and no cleaning then the silly piston might have an advantage.
The overpressure of the DI system will blow sand and crap out of the action long before the carbon build up will be a problem.
We had 11.5in Bushmasters in Iraq in 05 that had issues at first. Bushmaster got us different springs and buffers and they ran great after that.
Larry Vickers used to be pro-piston. Now he says they likely are only beneficial for sustained full auto fire.
