[rickdylan]

I'd suspect you must have read something the wrong way. I don't see how dust or sand could affect the two that much differently. The difference is cleaning, and how critical that was and how frequently the two needed to be cleaned and how easy it was to clean the two in remote conditions. The piston system is generally much easier to clean since you don't get all that gas and powder residue mixed in with the oil and grease of the bolt and bolt carrier.

[RKV]

Pretty sure I have not. Which is why I made sure that you knew that I got that info from Armalite, who was detailing who knows what tests.