BCM Standard 300 BLK Upper Receiver Group

Overview BCM’s Standard Upper Receivers are our baseline for price and performance, and their 300 Blackout models are no different. The continuous taper barrel profile found in these uppers provides excellent weight balance, keeping weight back towards the rear of the gun. This makes these uppers balance exceptionally well when paired with a suppressor, allowing the front of the gun to stay lighter and be more maneuverable even with the added weight of a can. As with all BCM uppers, you can expect superior fit and finish with thermal fit tolerances that increase overall consistency and service life. What’s Included 1x BCM Upper Receiver with BCG 1x M-LOK Picatinny section 1x BCM M-LOK QD mount Specs FEATURES Warranty: Covered by BCM’s manufacturer warranty. Warranty service is provided by BCM. UPPER FEATURES Manufactured by Bravo Company MFG, Inc. (BCM) Fully assembled, headspaced, and test-fired M4 feed ramp barrel extension and upper receiver for reliable feeding T-marked upper receiver for easy configuration of tactical accessories Mil-Spec barrel steel (Certified Mil-B-11595E) for strength and durability Chrome bore and chamber for enhanced chambering, extraction, and reliability Manganese phosphate barrel finish for corrosion resistance HPT / MP Inspected barrels for quality assurance and flaw detection BOLT CARRIER FEATURES BCM (MPI) complete bolt carrier group for AR-15, M16, or M4 Parkerized exterior with chrome-lined inside carrier Machined to USGI specifications, Full Auto Profile M16/M4 carrier with Mil-Spec chrome-lined gas key Gas key heat-treated and chrome-lined, securely fastened with grade 8 fasteners Bolt assembly machined from Mil-Spec Carpenter No. 158 steel, shot peened Includes tool steel extractor and ejector Includes BCM extractor spring HPT (High-Pressure Tested) and MPI (Magnetic Particle Inspected) BCM test fires for function before shipping Upper Specifications Caliber 300 Blackout Barrel Material 11595E Spec Steel Barrel Finish Manganese Phosphate (Mil-Spec A-A-59267) Bore & Chamber Chrome Lined Twist Rate: 1:7 Gas System Pistol Muzzle Device BCM® Comp Mod 1 (762/300BLK) Muzzle Threads 5/8×24 Made in the USA. BUFFER RECOMMENDATIONS INDEX: Sprinco Hot White: In the middle of a standard carbine spring and the Blue spring, roughly 7-8% stiffer than standard. Sprinco Blue: 15% stiffer than standard carbine springs. Sprinco Green: Rifle length spring for A5/MK2 buffer systems. MK2 9″, MCMR-8, Standard Barrel – Continuous Taper Profile, Pistol Gas Unsuppressed Supersonic Carbine: H1 or H2 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: -A5H2/T2 – Rifle or Sprinco Green Spring Law Folder, Carbine: H1 or H2 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H1/T1 or A5H2/T2 – Rifle or Sprinco Green Spring Suppressed Supersonic Carbine: H2 or H3 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: – A5H3/T3 – Rifle or Sprinco Green Spring Law Folder, Carbine: H1 or H2 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H2/T2 or A5H3/T3 – Rifle or Sprinco Green Spring Suppressed Subsonic Carbine: Carbine (3.0oz) or H1 – Standard Spring Vltor A5/BCM MK2: A5H1/T1 – Rifle or Sprinco Green Spring Law Folder, Carbine: Carbine (3.0oz) – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H0/T0 or A5H1/T1 – Rifle or Sprinco Green Spring 50/50 Subsonic / Supersonic Suppressed Carbine: H1 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: A5H1/T1 – Rifle or Sprinco Green Spring Law Folder, Carbine: Carbine (3.0oz) or H1 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H0/T0 or A5H1/T1 – Rifle or Sprinco Green Spring ** These are approximations. Due to the wide operating range of 300 Blackout, it is recommended that you do your own testing and confirm functionality. It’s also recommended to shoot the rifle for roughly 500-600 rounds to allow proper break-in and gas system sealing before arriving at a final buffer setup. TECHNICAL SPECIFICATIONS Specifications 9″, MCMR-8, Standard Barrel, Pistol Gas 9″, QRF-8, Standard Barrel, Pistol Gas Weight 3 lb 1.6 oz with Radian Raptor 3 lb 4.2 oz with Radian Raptor Weight, Standard Lower – No Stock 4 lb 13.1 oz with Radian Raptor 4 lb 15.7 oz with Radian Raptor Weight, Standard Lower – Law Folder, No Stock 5 lb 8.2 oz with Radian Raptor 5 lb 10.8 oz with Radian Raptor Length, Upper Only 17.75″ Muzzle Device to End Of Receiver 17.75″ Muzzle Device to End Of Receiver Length, Standard Lower – No Stock 25.18″ Muzzle Device to End Of Carbine Extension 25.18″ Muzzle Device to End Of Carbine Extension Length, Standard Lower – Law Folder, No Stock 26.38″ Muzzle Device to End Of Carbine Extension 26.38″ Muzzle Device to End Of Carbine Extension Length, Standard Lower – Law Folder, No Stock (Folded) 19.69″ Muzzle Device to Furthest point 19.69″ Muzzle Device to Furthest point