So... came upon this thread because I was trying to remove the baseplate of my Sug MPX magazine and up the capacity of a 10 rounder I accidentally purchased... (I’m lawfully allowed to have high capacity magazines).
The base plate of a factory 10 round magazine is CRAZY GLUED shut. Like tons of it. You’re going to have to break it carefully then add an aftermarket baseplate like one from Taran Tactical