REMOVAL AND INSTALLATION OF BOLT CARRIER BUFFER
To remove buffer from bolt carrier, remove all small parts from bolt carrier. Place wooden dowel inside bolt carrier and along with a hammer hit the wooden dowel until the buffer comes out.
Now take replacement bolt carrier buffer and align the buffer to the bolt carrier. You can use a firing pin to index it. While holding the firing pin in place, take a hammer and hit the buffer into place. Once buffer is in place and its index you may remove the firing pin and hit the buffer until it sits flush against the bolt carrier.
Once the buffer is in the bolt carrier you may reassemble the bolt carrier's small parts.