My Shield is only 2 weeks (new). Only shot 50 rounds through it. With slide locked back, both mags seat easily and do have a little wiggle. With slide forward, the 8 round mag seats pretty easy still, but the 7 rounder is almost impossible to seat.
I have fully loaded both mags and are letting them sit for a while. Also, been racking the slide and dry firing a lot to help break things in.
After finding some threads and videos about the mag release rust issues, I pulled mine out and inspected. No rust at all. Have not really seen any recent threads on this issue. Is this something that S&W has now corrected. If so, how? The threads state this part is plastic overcoating a metal insert. If so, how does the rust permeate out to the outer surface. Since the outer surface is polymer, I did not oil mine.