98src
06-01-2020, 02:57
I am a novice when it comes to the ar-15 platform. I just bought one of the Midway Bushmaster 450 caliber uppers in the 20" barrel versions. I have a AR-15 A2 rifle and a M4 carbine. Will the 450 upper work properly on either lower? The 450 upper has a "carbine length" gas system.