Think of it this way: The law is poorly written. To answer your question, it would have to have been specified in the law that "Pouring hot glue up to a certain point is acceptable, as is rivets, etc." Instead, it doesn't say anything about it.
So whatever your solution is, it just has to be reasonable to the Game Warden/Police/Prosecutor/Judge and Jury. So, really it's an impossible question to answer. Because reasonable to me is "the existing spring is enough to limit a 100 round mag to 15 rounds because the more you put in the tougher it gets" and to a shitbag gun banner like Polis it's something completely different.