Buffer Weights - Pistol Caliber Carbine
Colt 9mm Standard - 5.5oz
RRA 9mm Standard - 5.6oz (seen elsewhere as 5.4oz)
Colt 9mm A - 6.3oz
Colt 9mm B - 7.1oz
Colt 9mm X - 7.9oz
The standard versions can be used in .223/5.56 carbines. The A, B and X are designed for use in government full auto 9mm carbines with the B and X for suppressed as well. They can all be used in 9mm, .40cal, 10mm and 45 carbines that use a standard carbine buffer tube length.
TS