Alright, so I haven't painted that section black yet, and the integrated suppressor look idea didn't pan out, probably should have measured first lol, but still came out good, with 3 inches of outer barrel extensions.
I need to tweak the suppressor to stay locked on properly, or failing that jb weld it, but it's way cheaper than the other surefire suppressor replica out there, so I'm fairly happy with it, maybe a new flash hider would work better too, not sure.