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BCM® Barrels
M4 Feed Ramp Barrel Extension
In developing the USGI M4 carbine as one of the primary weapons for today’s infantry, some modifications were performed to the original M16 platform to enhance the reliability of the shorter barreled carbines. With the shorter carbine gas system and the increased gas port pressure, the carbine cycled faster, and at times the cycle rate could be faster than the magazine would feed ammunition. One of the modifications done to increase reliable feeding included enhancing the angle and the length of the feed ramps. This USGI modification was done to both the barrel extension and the upper receiver, creating a longer and steeper feed ramp. These Mil-Spec M4 feed ramps are part of the original CNC manufacturing process. As a result, the factory machined M4 feed ramps on the receiver are hard coat anodized which adds significant strength to the aluminum. This feature is offered on all BCM uppers and all BCM barrels.
5.56 NATO Chambers
The USGI 5.56 NATO chamber is the best choice for effective deployment, reliability, and compatibility, of higher chamber pressures of military ammo.
HPT / MP Inspected Barrels
Military specifications require that barrels undergo a HPT (High-Pressure Test) load as a part of quality assurance procedures. Commonly referred to as a proof load, the M197 HPT is rated for 70,000 psi. BCM barrels are proof loaded and then MPI (Magnetic Particle Inspected) to detect any possible flaws in the barrels surface. The barrels are MP inspected with both circular and longitudinal magnetic fields per ASTME1444-01 (current Mil-Spec) to assure a high quality finished product. All BCM barrels are marked HP MP as our proof load marking.
Mil-Spec 11595E - Barrel Steel
BCM Standard Barrels and Hammer Forged Barrels feature steel that is Mil-Spec per MIL-B-11595E (independently certified). This (CMV) steel is a Mil-Spec steel used in the USGI M16 family of rifles; it is stronger and will last longer than the typical barrels offered in the commercial market. The Mil-Spec grade steel gets its’ additional strength and rigidity from an increase in carbon and/or vanadium in the alloy. This will offer increased barrel life and performance through use in all types of extreme environments and temperatures.
Hammer Forged Barrels
This process of manufacturing barrels has been used for European small arms for generations, and it is gaining popularity in the United States because of the increased barrel life and outstanding accuracy of a hammer forged barrel. These barrels also use the certified 11595E barrel steel. The BCM BFH™ series of barrels are made right here in the USA! (Just like all the BCM products.)
BCM SS410™ Barrels
This BCM barrel is machined from a 410 stainless steel. It features hand lapped button rifling with a 1/8 twist rate and M4 feedramps. As with all BCM barrels it is proofed (HPT) and magnetic particle inspected (MPI). To give the shooter the best balance of weight and accuracy this BCM barrel has a mid weight profile. (410 stainless is a harder and more corrosion resistant than the conventional 416 stainless found in most barrels.)
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