I was looking at the Ruger American Ranch rifle in 300 blk, so I’d have a bolt-action suppressed.
See, when the action opens a lot of noise comes out, so all semi-autos are louder than bolt guns.
I was looking at the gas adjustment knob on my MCX and noticed a small hole and larger hole (low/high gas pressure). Shooting suppressed, the low is perfect IMO, if you goal is to have a semi-auto.
There are times when you want maximum noise reduction, but don’t care about follow up shots, or if follow up shots are needed, you can do that a bit slower by manually running the charging handle on the MCX.
So I did some tinkering and figured out if I move the gas all the way left and go past the detent, the bolt will not cycle and act like a bolt action! Only thing is, we MUST make sure the gas adjustment knob does NOT fly off, so it MUST be retained! and the adjustment knob doesn’t quite clear the underside of the rail/upper receiver.
I sanded/filed down just a little bit of the ear on the knob and now it clears and with some effort (using a bullet or multi-tool), you can adjust the gas to OFF with the handguard on. Its also easy to remove the handguard on the MCX, but both methods work after the slight modification to the knob.
If you do file, you need to cover the steel so it doesn’t rust or corrode. I suggest black cerakote; the heat treated version you can buy from brownells.
I’ll make a video, but here are some photos.
TIP. If you want to turn the gas all the way off and have your MCX act like a single shot while suppressed. Turn the gas knob all the way left, so from Low to past that detent. Tug on the knob and ensure it won’t fly off. You basically want the top ear to be at the 12 oclock position.
