Well, the only reason why it is hard to take out is that w/ the echo-1 m4, its attached to the stock and you must first take out the bottom of the hop-up unit. Today, we took apart my m4, and had trouble putting it back together since i am not as familiar w/ m4's internals as ak-47s, since i just got this one in the mail. now there's something wrong with it. the fuse blew, so we got a new one and pt it back together. Somethings wrong with the selector switch. Sometimes when u just switch it to semi it fires in automatic until switched to safe. Also, the rate of fire is a lot slower.. what should i do?