Rigging rotation squishy problem

So, to say, I’m very new to animating, and I’ve ran into an issue I’ve spend hours trying to fix, when I rotate the bolt on this rifle, it squishes it instead of rotating. When I rotate it, the bolt does not rotate, instead, it sort of rotates a face and not all of the bolt.

Please upload a file or provide more detail about the set-up.

No worries, I just worked out the problem myself ; It required me to preserve volume in the armature modifiers part. Thankyou for responding though ;D