The 13.9" has a .076 gas port diameter, which I verified with pin gauges. I'm running a VLTOR A5, A5H2 buffer, a Sionics M16 BCG, and a Dead Air brake. I also tried using a Wolff extra power rifle spring, but it was a no-go, so I ended up using a Sprinco green spring. .223 brass is ejecting at...