Okay, I'm coming up dry guys. I have a 12.5" CMMG .308 barrel. I'd like to put a blast deflector/flash can on it and weld it o get my 16" OAL. Everything I'm seeing is 3.25 or so. Even a 3.5" I'm thinking may end up being slightly short factoring in the barrel threads.

I know there are the 5.5" CAR-15 style brakes but I was hoping for something more like a Noveske, KAK, or krink brake.

Is there anything out there that I'm missing?

Any help would be greatly appreciated!

Why not sell the barrel and get a 16" one?  12.5" with a welded muzzle device to get to 16"  is a lose/lose.

Your not getting the benefit of handling the short barrel gives you (it's still 16"), and on top of that your loosing a great deal of velocity and hence energy with the short barrel.

Eh, you're not wrong. Still a project I want to try. I have a 16 already. This would be a spare upper.

I was initially going to build it as an SBR but once I started looking at blast deflectors I realized most were going to put it within a half inch to an inch of 16 anyway. May as well save $200 and the paperwork hassle at that point.