HausofArms has partnered with MGM (Match Grade Machine) in Utah and has done a special batch of these barrels to fill YOUR needs. These are TC Contender Stainless Steel barrels 16 1/4" long BULL contour (any factory rifle forend will work) chambered in 300 Blackout with a 1 in 8" twist, and is drilled and tapped for a standard TC 4 hole scope base. These barrels will fit any TC Contender as well as fit any factory rifle forend. WE HAVE CHOSEN TO THREAD ALL THE MUZZLES TO A 5/8-24 THREAD. MARTY
Dylan at MGM had some velocity testing on these calibers by an independent 3rd party, check out this link it is extremely informative and will answer alot of your questions regarding barrel length and velocity.