i got the upper back and a new piston was installed. the service quality and attention to my issue was handled in a very professional and timely manner. i was very impressed, thanks frank and chris.
i fired 180 rounds thru the upper when i got it back the next day. the first 30 rounds i fired in a slow and methodical manner, the last 150 rounds i fired with extreme prejedious and without hesitation. by that i mean each 30 round mag was emptied in 1 to 2 minutes. needly to say, i was very pleased with the results. they are as follows,,,
about half the rounds were unsuppressed and there was never a functioning issue even with both gas settings.
the other 90 rounds, i attached the silencer (aac m4 2000) and ran the upper with the gas piston on the 2 groove side and the 3 groove side. i really didn't feel the m4 2000 made that much more back pressure but i was using a 9mm buffer too.
my only cuiosity of the session was this,,i don't think the 9mm buffer is a good idea when using the 3 groove side on the piston UNLESS the can is in place. i had 2 rounds that seemed to short stroke using that set up. when the can is installed there was no issue at all however. the ammo at the time of this occurance was SA battle pack which is normally good stuff but is 20 years old.
so i swapped the 9mm buffer out with a H buffer and continued firing with the suppressor and changed the piston to the 2 groove side. never a hicup after that.
i really dont think the design of the POF warrents a extra heavy buffer though. 223 is such a light round anyway that in a semi auto form the recoil is so mild with any buffer, at least for myself. OCYYMV.
i will try the MGI buffer next week.
the ammo was fired was a mix of xm193, IMI military m193 type, winchester Q3131A, south african battle pack and some adcom m855.
i was very happy with the POF product that day and the suppressor helped keep my hands warm on the 45 degree arizona morning.