AAC 51T muzzle device on a DD Mk18 10.3"?

General Firearms NFA
1

I just purchased a DD 10.3" upper with the RIS II rail. From some of the older threads I found online there seems to be an issue running one of the AAC 51T muzzle devices that will clear an M42k or Mini 4 suppressor. Are most folks running additional shims or spacers with their AAC FH, brake or blackouts?

2

I do not use any shim or spacer with my AAC 51T Blackout on 3 different guns.

3

Good to know.

I found this photo from silencertalk where a member is having trouble getting his AAC brake on wit that RIS II rail.

4

If the wrench flats are behind the teeth it works. So the breakout and the (2.0) and blackout FH all work . If you are using the muzzle Brake, it will not.

5

I had breaks that would and would not work. I tried the first one and thought “WHAT”, changed breaks and it fit. So there are some different variations. Find one that does, seems jwknutson has given good advice. Mine has a break and works.

PB

6

I’m running the flash hider that came with my SDN6 on my DD Mk18 upper. I didn’t use shims, and it works perfectly.

7

I studied this goofiness when I was first trying to figure it out but forgot exactly what to look for. Wish I could give more feedback. I cant post pics, but if someone could take their can off and take a pic of their 51T it might give him more insight.