The grey factory mags in question from the OP are 10/15 round Sig factory mags, so I don't think the "before pinned" capacity means anything. A 17 round mag might still be stiff.
There is a level of correct spring tension that is optimum, obviously the ones in question are too stiff. Mine have eased up a little bit.
There is a level of correct spring tension that is optimum, obviously the ones in question are too stiff. Mine have eased up a little bit.




















































