ApD2

18" AP AR10, .308, .1098 and waiting for 3mm drill bits to enlarge port to .1110. Rifle buffer, rifle buffer spring. All AP. FailZero BCG. Factory port was .078 and it wouldn't run. Ammo was 150gn match bullets,LC brass. 42.5-43gn 4166 or 4895. Actually it ran ok for a few 100rds. Which took a while to achieve. Very accurate rifle. After a couple cleanings it wouldn't run. It wasn't ejecting then feeding a round on top of the spent brass causing lots of crunched wasted brass. I thought it was over gassed. Bought an adjustable block and that led me to conclude it was under gassed. Bored a .1098 hole and problem solved. Since Im running the gas block closed off at .1098 I want to farther increase the port to 3mm which I believe is between 17/64" and 1/8".1110. giving me room to adjust the block as necessary. My 16" AP also M5, 308 is running .078 port, .072 fact? carbine buffer and spring. The 16" has the S2? Smooth hand guard and she is lights out and wlll run 110 3200fps load up to Nosler 180green tips no problems. Just my experience. Both are fantastic, reliable auto-feeders with BDX optics and paired with a Kilo 2200 range finder.