Recently I was installing some proper retro parts in my Colt 601 "Project AGILE" clone. Of these the appropriate original pattern bolt catch is extremely hard to find, even from Mr. Thomas. So I was excited to have one in hand, and wanted to install it properly. While I was at it I figured I would share a little installation tip. Follow along and learn how to protect the finish of your AR-15 lower receiver while you are installing an AR-15 bolt release.