Rigging questions - How do I make the drum of this revolver rotate only from the center of a barrel/barrel to frame question I was wondering how I would make the drum of a revolver barrel rotate in a centered position so it can only spin and not actually change position if that makes sense.

My second question would be, as of right now if you rotate the barrel of the revolver -- it would fold into itself like so.Essentially, if you try to rotate the barrel it won't move on the right point, ie the little circular shape and fold into itself.

How could I make it so the revolver barrel rotates along the proper point in regards to the frame? ie that little circular point where the weapon root bone is.

Thank you so much for reading, and here is the blend file. https://a.pomf.cat/wkyqgw.blend

I would provide the pics but I don't have the rep. 

edit: First issue resolved by lemon, still need help on the second!
As the barrel is symetric, you can find its center in edit mode by selecting all the vertices and use ShiftS (snap), then choose "Cursor to selected".



Now back to object mode. You can add a single bone armature and it will be created at the 3D cursor position (so it is centered to the barrel). Simply edit it (if you want as it is not mandatory here) in order to align the bone tail along the barrel (but keep the bone head in place along the same Y axis).

The barrel will rotate around the bone.


Edit (considering the comments) :

You can parent the bone placed above with the "barrel" (?) bone in blue below.
Go to pose mode for the "barrel" bone. Select the previous bone then select the "barrel" bone and CtrlP then choose "bone".



But as you can see, you may adjust the "barrel_joint" bone before doing all that :