By now, most Shield 45 owners know about the revised, grooved magazine followers available from the factory to fix magazine drops while firing. The groove is supposed to prevent the follower from pushing the mag catch out of engagement with the magazine as it goes up inside the mag tube feeding rounds. For the most part, it works. BUT...
A continuing occasional problem with 45 Shields is mis-feeds where, during recoil, the next round catches on the locking block's lower feed ramp. The bullet is stuck nose down while the slide/breech face catches the rear of that cartridge case and sticks open. All you have to do is slightly slingshot the slide and the stuck round pops up and feeds properly. But, it is still a stoppage. The reason that happens occasionally is two-fold:
1) The mag catch protrudes just far enough into the inside of the magazine tube to hang up the follower slightly so it hesitates and doesn't push the next round up fast enough to feed properly during recoil, EVEN with the new groove!
2) The mag catch protrudes just far enough into the inside of the magazine tube to hang up the magazine spring just enough so it results in the same mis-feed as above, WITH or WITHOUT the grooved follower.
Well, so far, there's nothing I'm willing to do to cure #2 but, I certainly fixed #1 as follows:
S&W's grooved follower is still not grooved properly! The groove doesn't extend deep enough into the side of the follower or extend back far enough on the side of the follower to completely eliminate the slight hang up that still occasionally occurs as the follower slides up inside the magazine tube past the magazine catch. Therefore, you may still get occasional mis-feeds.
My fix is to re-groove all my 45 Shield followers sufficiently so they slide completely past the magazine catch without touching it at all. I set up my Dremel in its drill press and ran all my followers past the grinding wheel to deepen and extend the groove. Now, that problem is cured, once and for all.
As for the possibility of the spring catching on the mag catch, I haven't experienced it again in over 250 rounds of FMJ and JHP ammo. Hopefully, it won't happen again.