BCM Standard 5.56mm Upper Receiver Group

Overview BCM has been our go-to for many years because they do an outstanding job of balancing quality, price, and overall performance. These standard uppers still feature the fit and finish you’ve come to expect from BCM without all the bells and whistles of the MK2 receivers at a lower base price. While we thoroughly enjoy the improvements found in the MK2 uppers, the cost/performance ratio of the standard upper receivers is hard to beat. What’s Included 1x BCM Standard Upper Receiver Group 1x BCM Bolt Carrier Group 1x BCM M-LOK QD Mount 1x M-LOK Picatinny Section Allen Keys 14.5″ models are not pinned and welded from the factory, and the A2 device that comes with these uppers is not long enough to do so. You’ll need a trusted gunsmith to do this once you install the muzzle device of your choice. Specs 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 USGI 1/7 twist rate for versatility with various ammunition 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 5.56 NATO Chambers for compatibility with military and high-quality ammunition HPT / MP Inspected barrels for quality assurance and flaw detection BFH BARREL FEATURES Cold Hammer Forged Barrel USGI 1/7 Twist Rate Mil-Spec Barrel Steel (Mil-B-11595E) Chrome Bore and Chamber Manganese Phosphate Barrel Finish 5.56 NATO Chamber Government Barrel Profile HPT / MP Inspected STANDARD BARREL FEATURES USGI 1/7 Twist Rate Mil-Spec Barrel Steel (Mil-B-11595E) Chrome Bore and Chamber Manganese Phosphate Barrel Finish 5.56 NATO Chamber Government Barrel Profile HPT / MP Inspected 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, BCM Extractor Spring HPT (High-Pressure Tested) and MPI (Magnetic Particle Inspected) BCM test fires for function before shipping Warranty: Covered by BCM’s manufacturer warranty. Warranty service is provided by BCM. 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. 16″ MidLength Gas 14.5″ MidLength Gas 11.5″ Carbine Gas Unsuppressed Carbine: H1 – Standard Spring Vltor A5/BCM MK2: -A5H1/T1 – Rifle or Sprinco Green Spring Carbine: H1 – Standard Spring Vltor A5/BCM MK2: -A5H1/T1 – Rifle or Sprinco Green Spring Carbine: H2 – Standard Spring Vltor A5/BCM MK2: – A5H2/T2 – Rifle or Sprinco Green Spring Suppressed (Low BackPressure) Carbine: H1 – Sprinco Hot White or Blue Spring Vltor A5/BCM MK2: – A5H2/T2 – Rifle or Sprinco Green Spring Carbine: H1 – Sprinco Hot White or Blue Spring Vltor A5/BCM MK2: – A5H2/T2 – Rifle or Sprinco Green Spring Carbine: H2 – Sprinco Hot White or Blue Spring Vltor A5/BCM MK2: – A5H2/T2 – Rifle or Sprinco Green Spring Suppressed (High BackPressure) Carbine: H2 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: A5H2/T2 – Rifle or Sprinco Green Spring Carbine: H2 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: A5H2/T2 – Rifle or Sprinco Green Spring Carbine: H3 – Sprinco Hot White or Blue Spring Vltor A5/BCM MK2: – A5H3/T3 – Rifle or Sprinco Green Spring TECHNICAL SPECIFICATIONS Specifications 16″, MCMR-13, Government Profile, MidLength Gas 14.5″, MCMR-13, Government Profile, MidLength Gas Weight 3 lb 15 oz 3 lb 12.5 oz Weight, Standard Lower – No Stock 5 lb 10.5 oz 5 lb 8 oz Weight, Standard Lower – Law Folder, No Stock 6 lb 5.6 oz 6 lb 3.1 oz Length, Upper Only 24.6″ Muzzle Device to End Of Receiver 22.9″ Muzzle Device to End Of Receiver Length, Standard Lower – No Stock 31.9″ Muzzle Device to End Of Carbine Extension 30.2″ Muzzle Device to End Of Carbine Extension Length, Standard Lower – Law Folder, No Stock 33.2″ Muzzle Device to End Of Carbine Extension 31.5″ Muzzle Device to End Of Carbine Extension Length, Standard Lower – Law Folder, No Stock (Folded) 26.6″ Muzzle Device to Furthest point 24.9″ Muzzle Device to Furthest point Measurements are an approximation and can vary slightly between uppers.