The BF-10(TM) is a loading device used for reloading an AR-15's magazine in a Fixed Magazine firearm. It performs the same function as a stripper clip for an SKS or similar rifle. How it works The BF-10(TM) must first be filled with cartridges. This is done by simply pushing them into the cartridge-shaped opening at the end. A retaining tab keeps the rounds securely held in the BF-10(TM). When the last round is fired from the rifle, the bolt will lock back. The BF-10(TM) can then be inserted into the ejection port and "rocked" to lock it in the correct position. Then the rounds can be pushed into the fixed magazine with the natural motion of squeezing the handgrips and sliding them all the way toward the rifle. When the magazine has been filled, the BF-10(TM) can be rocked out of the ejection port. The bolt stays back, allowing the user to chamber a round via the bolt release paddle as per normal AR-15 operation and resume firing.