Least "gassy" 556, 11.5 inch(or so), piston, AR and Suppressor Combo?

Nomad0001 said:

Considering Sig MCX LT. New to AR pistols AND suppressors (I hear new flow through suppressors help). Price around Sig MCX plus Can, but flexible if a better product is available.
Thx!

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I always preface these posts by saying there are people on this forum with more experience than I have but here it goes.

If you want a gun that is less gassy, the first thing I would do is get one with an adjustable gas block. Not an adjustable gas block like the Sig you mention but an actual adjustable gas system. My personal preference is installing a rifle speed adjustable gas block because of ease of use. While they work, the detent key systems always aggravated me as I switched from suppressed to unsuppressed. The rifle speed system is a rotary numbered system and you just dial it to your preferred settings. Another system I have used that does make a difference and is easy to use is an adjustable gas BCG like the Bootleg. You can make adjustments pretty easily.

The second thing I would look at is a good flow through suppressor. I have several including the HUX, the KAC, and the Surefire and they all make a big difference. There are another half dozen and almost all of the 3D printed cans that were designed to be flow through work pretty well.

The third thing is your charging handle. You want it to have a good seal and vent any stray gas. I have had good look with Radian, Geissele and the newer Daniel Defense charging handles.

The fourth thing to be aware of is that a lot of really well thought of, ultra reliable ARs are ultra reliable because they push a lot of gas back. It is so they will work and continue to function even in adverse conditions (looking at you LMT, HK, DD, FN and others). For the more milspec ARs, I have found the piston rifles with a flow through can are a little less gassy than the DI but it is so close that I am not sure it makes much difference.

Any rifle utilizing the adjustable gas block plus a flow through plus a good charging handle will make a big difference. It is most notable with higher rates of fire. If you are going at a leisurely pace when you shoot, there is less difference.

I haven't noticed my Spear LT being over gassy compared to any other AR... I've been pleased with it

I have an 11.5" Triarc (not their suppressor-only gas port), fixed gas block and a HUXWRX and it's good. If less gas out of the ejection port is relevant, I have had good results with KAK's down vent carrier.

I also have a 10.5" Criterion with a Superlative Arms piston kit and the HUXWRX and that's my go-to for indoor stuff, where the less gas in face is noticeable.

The newly released HK MR556 fits your requirements. Suppressed and normal gas setting, and within that, you can swap gas vents to reduce the gas to your exact preference. Available in 16” and 11” configuration. Guaranteed 10 shot 30mm (almost exactly MOA) accuracy with free barrel replacements for life.

The flow thru designs like Huxworks 556K will be the lowest back pressure. Legacy low back pressure cans like the Surefire RC2 would also be excellent, with better durability and sound reduction.