All Wilson Combat Match Grade AR-15 barrels are precisely crafted of the finest American-made 416R rifle rated steel on computer controlled equipment to our exacting list of technical specifications. These proven barrels feature a hand-polished bore and feedramps and then complete a rigorous final inspection process that ensures your new barrel will meet your most demanding expectations. All barrels feature crisp CNC markings, precision muzzle crown and a chamber and gas port optimized for reliability.300 HAM'RThe 300 HAM'R was developed for optimal terminal performance in a standard AR rifle - and offers near .308 Winchester effectiveness while exceeding the ballistics of the famous 30-30 rifle - the most popular hunting cartridge of all time.The 300 HAM'R cartridge has 18% more retained velocity, 40% more energy and a 56% flatter trajectory than the 300 BLACKOUT at 200 yards! The 300 HAM'R has amazing accuracy and low recoil in a lightweight, compact standard AR platform rifle that uses a standard 5.56 Bolt. We recommend a 300 Blackout magazine for best overall reliablilty. Ammuntion and reloading dies/info is available from Wilson Combat.Wilson Combat SBR Tactical Profile BarrelsTuned for outstanding reliability, the Wilson Combat SBR (Short Barreled Rifle) Tactical is our smallest Custom High Performance AR rifle barrel. Highly portable and hard hitting, the SBR Tactical upper will transform your registered lower into a superior carbine for close quarters operation. Medium taper is ideal for high rates of sustained fire. You will love how quickly and easily the SBR Tactical balances and shoots.NOTE: When assembled into a Short Barreled Rifle, all NFA rufles apply.Specifications:Chamber: 300 HAM'RFeed Ramps: M4 StyleFinish: Matte Bead-Blasted StainlessGas Block Seat: .750 Diameter by .920 Length - Dimpled for Set ScrewGas System: Carbine LengthLength: 11.3Material: Stainless Steel, Type 416R, Barrel GradeMuzzle Threads: 5/8 x 24Profile: SBR TacticalRifling: 1:13, Precision Button RiflingWeight: 21 oz.