Suppressors S&W M&P 15 300 AAC question

[tacgnut]

Just took delivery of this sweet little AR with the sole intention to use sub sonic ammo with suppressor attached. My concern is whether or not the rifle will function with subs. After getting the rifle I read an article where the rifle functions flawlessly with super sonic ammo but not so much with subs, although they were not using a can.
My thought was to open up the gas hole and add an adjustable block, although this would void any manufacture warranty.

 

[Pappasniper]

Re: S&W M&P 15 300 AAC question

Open up the gas hole and you will need a gas mask to run it. Don't do that.

The gun is not designed to run subs in 5.56 , that ain't going to happen. You can shoot it, and then manually cycle it. Leave all that business to the 300 black out.

 

[lame deer]

Re: S&W M&P 15 300 AAC question

Hi, first post here but long time visitor. Have one of those M&P 15 in 300 Whisper (Blackout) with a Gemtech HVT. It cycles fine with factory Hornady 208 AMAX, haven't tried it without the suppressor yet and haven't tried my own reloads that i use with my T/C encore. Trigger on mine was kinda heavy installed a Geissele, much improved.

 

[shoot4fun]

Re: S&W M&P 15 300 AAC question

I bought the T style 300 Whisper/BLK upper from S&W. It has functioned 100% on my lower with both sub and normal loads from Hornady & Remington. I am using a YHM suppressor though.
DO NOT open up the gas hole as it will void the warranty.

 

[springer01]

Re: S&W M&P 15 300 AAC question

Having a can on it is going to be the key to it cycling subs. Why would you want to shoot subs without a can anyways?