I was shooting my 16s suppressed for the first time in several years and noticed that it was very gassy. I pulled the can (AAC m4-2k08) and shot it unsuppressed on the suppressed setting. It cycled fine on the suppressed setting. Then I set it to the normal setting and it felt identical. So I pulled the gas valve and noticed that the two ports appear identical in size. I did not mic the ports and I don't have pin gauges. Anyone know if the civilian SCAR gas valve has a true suppressed setting? I thought the SCAR valve was similar to the AUG, in that in order to lessen the amount of gas driving the system, it vented more gas from the gas block. After looking it over in more detail, this does not appear to be the case. It appears that the valve cents to the front and from the side of the port, and the amount of gas vented doesn't change based upon the position of the valve.

My rifle is an early import, one of the first after the "limited edition" massively overpriced first imports.

I have a similar experience of "extra gassy" with my 17.  Usually the gas regulator and gas manifold are really carbon fouled and a good cleaning solves the gassiness.

Check the gas regulator and make sure all the little ports are cleared out.  Also clear out the inner surface area of the gas regulator.

Go to parker mountain machines website and order some gas jets to try ..... Find which size works the best for your rifle/suppressor setup

I believe you can also order a gas jet kit from handl defense

They are super easy to swap

Basically what I did is I kept going smaller on my jet until the rifle wouldn't cycle reliably and then I went up one size

The suppressed setting allows the two small ports to vent excess gas through a slot at around the 2 o'clock position (when looking at the muzzle).

It appears as though those two ports will vent both in the suppressed and unsuppressed setting. I need to look at it in more detail.

EDIT:
Ok, thanks I see it. Moving to the suppressed setting puts those two small ports adjacent the exhaust recess/slot in the gasblock. I bought a second valve and may start very slightly enlarging the two exhaust ports.

It's much easier and repeatable to just change the gas screws. They come in 0.05mm increments and are easily removed with a 4mm screwdriver.

The way I set mine up was to start small and keep going up until the bolt locked open on the last round fired (short stroke test) and then went up 0.1mm in size.

AJ

Thanks for the suggestion re: the gas screws. I'm still curious to try opening the exhaust ports in the gas valve. I bought a spare valve and think I will very incrementally open the exhaust ports.