Diesel,
You are aware that by going to a 14.5" Barrel it becomes a Short Barrel Rifle according to ATF rule and requires registration and a $200 Federal Tax Stamp. Once an SBR always an SBR. The exception is for example if you would have the 14.5" Barrel with a Vortex Flash Hider permanently affixed to the barrel. (Pinned & Brazed).
My suggestion unless you have the proper tools like a torque wrench, barrel nut tool, receiver block, head space gauges and etc. I would just buy a complete upper with the bolt carrier group already in it. This will also assure everything is correct.
03
You are aware that by going to a 14.5" Barrel it becomes a Short Barrel Rifle according to ATF rule and requires registration and a $200 Federal Tax Stamp. Once an SBR always an SBR. The exception is for example if you would have the 14.5" Barrel with a Vortex Flash Hider permanently affixed to the barrel. (Pinned & Brazed).
My suggestion unless you have the proper tools like a torque wrench, barrel nut tool, receiver block, head space gauges and etc. I would just buy a complete upper with the bolt carrier group already in it. This will also assure everything is correct.
03