>>9566196>>9566199>>9566234Okay, if there's any good news here, it's that I was able to get the right bicep to function without the peg snapping. Now I have a functional right arm from this copy and a functional left arm from my previous one, meaning I can now make one whole non-defective figure to keep between the both of them.
So what I did to ensure the right arm didn't snap:
I boiled that arm to make sure it was good and loose. This was a risky proposition in and of itself, because it made the peg itself a bit rubbery and unamenable to twisting due to its having too much "give" and therefore diminished torque as I applied pressure. However, it worked, and as soon as I was able to get the bicep to swivel AT ALL I squirted some mineral oil inside the joint to get it lubed. Now, I'm able to swivel it without fear of it snapping it (well, at least for a bit, since it seems that's it's already beginning to tighten again, but you get the picture).