Tiger Rock AR-15 Rifle Length Buffer 5.6 OZ Rifle Length Black. The RR buffer uses a Carbine length extension as a base to shorten the buffer tube & reduce the amount of distance that the Rifle Recoil Mechanism has to travel. As the AR Rifle length buffer is installed the AR Rifle length buffer becomes permanently attached to the end of the barrel and is in the 'locked' position. It is a simple drop-in installation by removing the end cap and extending the bolt to the desired length. Package Contents: Tiger Rock AR-15 Rifle Length Buffer Rifle Length Tiger Rock B-LB: AR-15 Rifle Length Buffer -5.6 OZ -Rifle Length (BLACK) Black