I have a 14.5" pinned in 9 mm...just to try it..
It chronographs slower than the preferred 16" by a fair amount but only 1.5" shorter.
For me the pinned 14.5 ain't worth the trouble, I hardly ever use it.
The 16" is perfect for 9mm and it's still gaining speed, cause I chronograph the 10.5, 14.5, & 16" in 9mm.
Then disassembled the 10.5" for good, only a few ounces in weight, and you get higher velocities, better accuracy, and greater shoot ability.
The cool factor of short AR barrels wore off quickly for me, as not practical.
That's true across all calibers...nothing shorter than 16" for me...
I forgot I did have a 5.5" 9mm but gave that barrel away right after I tried it..been there.