Small Gas Port Runs A5H4? Anomaly?

[Ajackz]

Hey Guys im a bit confused right now.

I ordered a .067 gas port insert from BRT for a dedicated suppressed midlength 16 inch 5.56 gun. I have it installed in an A2 front sight post. On a springfeild armory saint barrel. It was about 55 degrees on the range.

I wanted to see how it would run unsuppressed so I went to the range with a stack of A5 buffers, a springco green spring, and some varying used rifle springs. Thinking that this would be lucky to lock back on an a5h1, I started testing xm193 with a old worn out rifle spring and the A5H0.. Last round bolt hold open no problem. I continue the process upping the resistance and lowering the bullets power until I am shooting American Eagle .223 with the springco green spring and an A5H4. With Lock Back! Unsuppressed.

Is my BRT insert probably the wrong size or are these results typical?

BRT said they typically recomend a .073 for these type of application.

[mpom]

Things might change when action is dirty. You could try PMC 223, known to be low powered.

[prepare]

I've got a 12.5 with .067 and the A5H2 buffer that runs fine unsupressed. The reduced gas port tamed the recoil so the gun cycles smoother and shoots flatter.

[Rayrevolver]

Micromoa sold gas block plates with a 14.5/16 mid suppressed setting of 0.055. For 100% suppressed, I would assume it would have been in that ballpark.