Mandrel

What is that, T-Bolt?

It's a mandrel.  Shove that up the back end of a particular brand of magazine, squeeze em in a vise with the threaded rod touching the bench surface, and now you can straighten out them feed lips

Probably an exercise in futility. But we will see.

That spring... It only goes in one way.  There is a front and a back to it as well as a top and bottom.  And screwing THAT up maybe a source of some of tears and whining.