If you are using the longer, heavier bullets in your AR-15, then you need a Sinclair AR-15 Single Shot Follower. The longer, heavier bullets are normally loaded longer than magazine length. The Sinclair AR-15 Single Shot Follower positions the 223 Remington cartridge loaded with longer bullets correctly for smooth feeding into the chamber. Once a round is fired, the bolt retracts and locks behind the follower in the empty/loading position. No need to take your magazine apart! It takes only a few seconds to install the Sinclair Follower on top of the existing follower. It can be removed just as quickly. This follower addresses many of the problems with existing single shot followers on the Mfg: Sinclair International