12.5" BCM Upper Receiver Group MCMR-10 Handguard

The BCM 12.5" carbine receiver was designed for shooting professionals and responsible civilians with the Mil-Spec features for the demands of their duty. It is fully assembled, headspaced and test fired. The Mil-Spec steel that is used to make the barrel is extremely strong and will last longer than the typical barrels offered in the industry market. 

Features:

• M4 Feed Ramp Barrel Extension
• M4 Feed Ramp Flat Top Receiver
• T-Marked Upper Receivers 
• USGI 1/7 Twist Rates
• USGI 5.56 NATO Chambers
• Mil-Spec 11595E - Certified Barrel Steel CMV
• Chrome Lined Bore and Chamber
• Manganese Phosphate Barrel Finish
• MPI Magnetic Particle Inspected Barrels
• HPT High Pressure Test Barrels
• Carbine Gas System
• MCMR-10 M-LOK Rail
• BCM C158 BCG
• BCM MOD4B Charging Handle

A gas expansion chamber is machined above the charging handle track and is combined with duel vents. These duel vents are machined at the rear, each side above the charging handle tech. This gas expansion chamber and duel vents help to redirect the vent gas away from the shooters face.  

The phosphate barrel finish creates a porous surface to absorb oil and to resist against corrosion from the elements. The barrels are required to undergo a HPT and MP inspection in order to detect any possible flaws and to assure a high quality finished product. The USGI 5.56 NATO chamber is the best choice for effective deployment, reliability and compatibility.