CA M24 bolt won't pull back
 

I loosened the hop up screw and now I can't pull the bolt back. It's just stuck. Any idea what I can do?

For some reason it works now. I was able to apply a bit of force to the bolt without breaking it. I'd still be interested to know if that's normal? What could have happened? I'm not sure it's the hop up screw since it seems intact.

Is there scratches on the cylinder head where it would enter the hop up chamber? I did the exact same thing first time I got mine, as it was my first airsoft rifle, so I backed off the hop up adjustment screw too far, so when the cylinder head went in, it got jammed with the screw sticking out too much. Had to tear apart the rifle to get it out, luckily, because the head is tapered, it didn't affect air seal. If you see scratches, then you can guarantee it was from it catching on that screw.

Yes it was. It's a common problem. Screws stick out too much and the nozzle gets stuck. Such a dumb way to adjust hop up too. I should the TDC mod which allows for external adjustment.