Shooting the Lightweight AR15 Pistol Project – Loads for AR Pistols & SBRs Part 2

All loads were fired over an Oehler 35P chronograph at a distance of five feet from the muzzle at eighty degrees Fahrenheit.

The first testing was conducted with a bare muzzle. Also, I completely shut the gas block off and fired five rounds. The velocity was 2290fps with a standard deviation (SD) of 6fps. With the gas system off, the gun did not cycle between shots.

I incrementally opened the gas system one ‘click‘ at a time. The Superlative gas block has notches in the valve that you can open using a supplied wrench. I had to open the valve five clicks before the weapon would begin to cycle. The velocity at this point was 2285fps with an SD of 12fps.

The weapon would not cycle reliably until I opened the valve to click ten. At this point the bolt traveled a full stroke and locked back when the magazine was empty. The velocity at this click was 2277fps with an SD of 15pfs. I considered this to be the most reliable gas setting with this factory load.

I opened up the gas system a click …Read the Rest

Source:: AmmoLand