It's on a SBR lower so no worries about legality, it's 14.5" now. My only concern on length is whether I can clear the rail with my suppressor. I've measured the OD of the undamaged threads on the barrel with a set of dial calipers and two different micrometers and I'm getting between .5025"-.503" which is larger than they should be. I'm hoping Rainier will replace the barrel for me.
it's not a proper way to measure the major dia. of the thread. find someone with a +/- reamer set, drill and ream a hole through a piece of 1/2" steel to .501" or .502", see if the thread can pass throu.
to properly measure the minor dia of the muzzle device thread you need gauge pins.