This Vltor A5 Recoil System Buffer is a high quality component that can be used to tune the recoil impulse or cyclic rate of an AR-15 rifle equipped with the Vltor A5 Recoil System. Notes:This buffer is designed specifically for use in the Vltor A5 Receiver Extension Buffer Tube, and will NOTfit in a regular AR-15 carbine or rifle tube. Attempting to use this buffer in a standard length AR-15 carbine or rifle buffer tube Could Result in Damageto the host firearm.