I have a weapon which I've rigged using the Skin modifier. After animating most of the animations I discovered one of the bones ("bolt") has it's pivot in the wrong place - which unfortunately I need to fix. If I remove the skin modifier, fix the pivot position and reapply the skin modifier the whole weapon offsets to one…
turn off always defeorm in sdvanced settings of the skin modifier, position everything and turn it back on. it helps if you do all this at a frame where it's in the bindpose