How exactly does the bolt catch and charging handle work? Does it matter which one you use? Do you always have to use one of them when you insert a new magazine? Sometimes when I insert a new magazine and pull the charging handle, a round comes out of the ejection port. Not because of a misfire or anything, though. I'm assuming that pulling the charging handle wasn't needed and it forced out a perfectly fine round? My question is, how do I know when I'm supposed to pull the charging handle and when I can simply just start shooting? When can I use the bolt catch?