Last week, I got a few hours at the 10th Annual USASOC Sniper Competition At Fort Bragg’s famous Range 37. One of the companies I spoke with was CMC Triggers who showed me their new Suppressed Optimized Bolt Carrier Group – Enhanced 223/556 AR15. It is a new version of their Enhanced Bolt Carrier Group but intended for use with suppressed rifles. Some suppressor optimized BCGs are so tuned, they only run when a suppressor is presemt. This one eas designed to still work, even when the suppressor is removed.
The flared rear of the enhanced bolt carrier is designed to reduce carrier tilt/cant during recoil and increasing reliability by strategically relocating key bearing surfaces.
The Bolt is “true” Mil Spec dimension and external surfaces are CNC ground after heat treat for a precision fit. These bolts are held to the highest possible tolerance possible. The “trumpet” area behind the gas rings, where carbon normally collects, is precision CNC Ground after heat treatment, to ensure as smooth of an area as possible, easing clean up, and longevity.
• 9310 Case Hardened Steel
• All Bolt components Shot Peened & Black Nitride coated
• 4340 Steel, Manganese Phosphate coated
• Magnetic Particle Inspected (MPI) and High Pressure Tested (HPT)
• Black Nitride low friction coating
• Mil Spec Extractor Spring & O-Ring
• 556 223 and 300 Blackout Compatible
It features a Black Nitride Plus finish which you mave have also heard referred to as SBN (Salt bath nitride) and sometimes QPQ (quench polish quench). All of these are a form of nitrocarburizing which is a chemical hardening of steel.