Re: 300 BLK MK12 MOD0 upper
Nice build. I just finished mine as well.
Noveske 10" barrel with a Troy TRX Extreme Rail and AAC Breakout. I'm waiting to get the new AAC 762 SDN-6 can.
My lower is a T15 BDX lower, Magpul ACS stock, JP tactical fire control group, and BCM Bolt Carrier Group...