Hand Gun 1.1

A gun a made today. I know it looks really bad but I'm really bad at things like that.
Also the gun was made to shoot and it was working until I put the pieces on top (the black pieces). If anyone can figure out why it would be a big help and I'll put it in an update (with credit of course).
-Thanks
Edit- I couldn't get it to work so I put them side by side