Adjustable gas key

[LRRPF52]

Think about it. High pressure gas/plasma is expanding behind the projectile down the barrel, with enough force to spit a substantial little piece of metal out at anywhere between Mach 2 and Mach 3.

When that high pressure gas/plasma cloud passes your gas port, it follows the path of least resistance up through the port hole, into the gas block, then the tube.




With most of the gas systems, you are above 10ksi at the port. If we go ahead and introduce a choke, like a set screw or plate with smaller hole above the port, pressure will be contained in the port longer, which is why we get tuned reciprocating mass effects from an adjustable gas block.

With the pressure containment/choking in the gas port area, we will naturally see increased port erosion, with more need to dial down the gas.

The adjustable key eliminates this problem, which is why I kinda like the idea of it over a gas block. The main disadvantage is having to remove the BCG to make adjustments.