I think a 14.5 inch with a mid length gas system can shoot phenomenal. If you get the pinned on suppressor attachment you do not lose anything. Having the pinned muzzle device is really nice as you don't have to worry about it coming unscrewed one day while trying to take your suppressor off. Just make sure you go all in and buy a system that comes with the gas block pinned.
The Geiselle URGI or similar comes to mind.
Mine shoots around 1 inch groups and is as smooth as a rifle system. Don't forget to buy a sling and a flash light.
This my 14.7" pinned/welded, mid-gas. One of my favorites.
![[Linked Image from i.imgur.com]](https://i.imgur.com/533x1qC.jpg)
