I have a Remington 51 that came with the original magazine. But a replacement magazine has given me problems in ejecting and loading a new round. I find that I have to hold the grip saftey very hard to get it to reload a new round but it still fails most of the time. The older real magazine works every time. Early in the week I went to the range and the first 10 shots worked okay but then it started not ejecting properly. Can't really tell if it's me or the gun.