The AR-STONER AR-15 Bolt Carrier Group in 9mm Luger is ready to drop into your AR-15 upper receiver build. This universal, ramped, 9mm bolt accepts both Glock and Colt style magazines. No matter if you are building a dedicated 9mm AR-15 or modifying your current setup this affordable and reliable part is a must have. Notes: The use of a 9mm Buffer is recommendedUpon installation, headspace should be verified by a qualified gunsmith