I was in the same boat as you not to long ago. From the research I did, people were generally advising against it due to the decrease in dwell time. In a recent SOLGW Instagram post, some one brought up a similar question with a 12.5 midlength. The response from SOLGW was that it was almost as bad of an idea as a 16in rifle length due to dwell time. Then stating that for a dedicated suppressed set up it would be "fine" because the can would "force" the gun to work. For my own anecdotal experience, I purchased a larue ultimate upper kit in 12in, they don't list there specs for the barrel on the website, but I purchased a 12in barrel it appears to be a carbine length and it shoots just as soft as my 14.5 pws midlength. 500 rounds later no hiccups yet but I will let you know if any problems do arise.