I finally got a suppressor for my 16S. Took it out to try it for the first time and it went from feeling like a smooth shooting .223, to kicking like a .308. With lots of gas blowback. My wife only shot about 10 rounds and decided she was done due to all the gas in her eye. The gun shot exactly the same on either gas regulator setting.  

So I did some research and ordered new gas regulator screws from PMM. I’m going to start by dropping from 2.0 to 1.70 to see how it goes.

I installed the 1.70 tonight, and as I was reassembling everything I noticed some things with the gas regulator I’ve never known or noticed before….

So there’s two holes next to each other:


And two tiny holes next to each other in more of a front and back orientation:


In my head I’ve always assumed one or both of the big ones were the non-suppressed setting, and the tiny ones were the suppressed setting. But after reinstalling it, I’ve realized the two tiny ones never align at the 6 o’clock position with the gas regulator screw. And the two larger ones, which I now realize are the two gas settings, appear to be the exact same size.

So questions:

1. What is the purpose of the two tiny holes on the side of the regulator?
2. Is it just my eyes, or are the gas setting holes the same size?
3. And if they are, how the hell do they work?

I know FN’s official position on civiy SCAR’s is there is no suppressor setting and suppressing them can void your warranty. I always assumed this was just lawyer speak for “there’s to many different bullet and suppressor brand combinations we have never tested, so we won’t warranty it”. But now I’m curious if they keep the holes nearly the same to essentially make it not actually a suppressor setting.

The gas regulator threads have a lot of people saying “the gun shouldn’t work in the suppressed setting unsuppressed. But looking at the holes on the regulator I don’t see how that’s possible.

It vents more gas into the atmosphere, what suppressor are you using? The PMM jets will help the recoil and bolt speed, the extra gas in your face is what it is, a gas jet won’t help that.

Two tiny holes are there to vent excess gas during suppressor use...when switched...


Gas jets are a must. One of the easiest mods to do is the mototech three position gas selector...

Also it varies a lot depending what suppressor you using...

Checkout mototech, they make a part called the Scar-burator that's basically an adjustable gas plug. They also make a gas plug with 3 settings for a second suppressed setting

Thanks guys. Suppressor is an M4-2000.

Both PMM gas jets and Mototech gas regulator are inbound.

Yeah M4-2000 is quiet but its dang gassy thus creating overgassing...you will be fine once you install the goodies...