Supressor questions

[CLP]

I have an AR-10, 20", and was wondering the following:

- Can a subsonic round with a supressor attached to this barrel cycle the action?

- If so, how do you work up a subsonic round? A reloading question for sure, but since I'm here...

 

[Zak Smith]

It's unlikely to work.

.300 Fireball (AR-15) uppers generally use "pistol length" gas systems to get enough gas pressure/impulse to cycle the (lighter AR-15) action.

 

[CLP]

So then am I to understand that I could do one of the following:

- Have an AR-10 that I've place a supressor on and shoot normal loads out of. The drawback being that there will still be a sonic crack- correct?

- Or, load it with sub-sonic ammo but end up having to manually cycle the action.

Is that about right?

 

[Zak Smith]

More or less, yep.

 

[bpsig]

Or put in an adamsarms kit. change setting to more gas and will cycle with sub's or turn off gas and back to bolt gun like.

 

[Coltdriver]

An adjustable gas block can be used to change the cycle characteristics. 300 Blackout can also use a carbine length tube with an adjustable gas block. Just a pain to go back and forth. I did see one gas block that was switchable but it was aluminum and set screw as opposed to clamp on type.

 

[rjrivero]

Or put in an adamsarms kit. change setting to more gas and will cycle with sub's or turn off gas and back to bolt gun like.

This isn't going to work. The settings on the Adams Arms Piston kit is "Full/partial/off"

So what you have is FULL GAS for normal use, Partial gas that reduces the pressure for use with a suppressor, and off that allows you to use the gun as a single shot.

The partial gas setting is used for suppressed guns because you increase the back pressure when you put a suppressor on the gun. This helps keep the gun from over gassing.

So, there is NO SETTING in an ADAMS ARMS kit that will allow you to cycle SUBSONIC 308 in an AR-10 that is set up to run with SAAMI or NATO spec ammo. You are taking the operating pressures and dropping them into .45 ACP range. That's just not going to cycle an AR-10.

An adjustable gas block can be used to change the cycle characteristics. 300 Blackout can also use a carbine length tube with an adjustable gas block. Just a pain to go back and forth. I did see one gas block that was switchable but it was aluminum and set screw as opposed to clamp on type.

I don't know if this is a viable option either. The AR10 Action is significantly heavier than the AR-15. The length of the gas system on the 300BLK and the "parent" cartridges has traditionally been of the pistol length variety. I know AAC is touting carbine length gas systems in their 16" guns, but they much more versatile in the pistol length gas systems with adjustable gas blocks.

I don't know if you can open the gas port big enough to cycle the heavy AR10 action on a long gas system. I think the physics of the ordeal are just too great.

If you want to run subsonic 308 bullets in a semi-auto, I think the 300 BLACKOUT/Whisper (R)/Fireball is (are) the best option....IMVHO.