[DreamSword]

I looked up a couple videos of the figure for reference since I don't own the figure myself, and from what I can tell it looks like you got hit with a rare case of bad QC.

Understandable you'd be scared of breaking him considering the pricepoint. But yeah, warming the arm up, removing it, adjusting the cap, and then popping the arm back in is about the only thing I can think of. Up to you if you wanna risk it though.

Sorry I wasn't too much help. This is a rather unique issue.