Mine was fine for the first 150 rounds then both mags started to drop frequently. I sent it back and just received it back. They replaced both mag followers and that was it. Took about 6 weeks to get it back. I was skeptical of the repair, but I just put 220 rounds through it yesterday with various target and defense loads and had zero mag drops and no other malfunctions. The follower passes by the mag catch with 4 to 3 rounds left in the mag. If there is any excessive follower dimensional variances, then it could definitely result in a premature mag release under recoil, so I am pretty sure that was what was occurring in my case. I'm going to buy some spare mags soon and make sure they work. I can't explain why it took 150 rounds to intially start occurring, but it could have been how long it took for a little magazine and mag catch wear to develop. If the followers were oversized just a bit, then that may have been enough to allow the follower to knock the mag release tab off the mag catch notch. S&W only replaced the followers on my mags. The mag body still had wear on it as did the mag catch tab, and the followers definitely looked new, so I don't think they replaced anything other than the followers which was consistent with what their documentation stated. Looks like they nailed the fix on mine. I'll just need to be sure to run in any new mags in the future to ensure they are good to go. I picked up a sweet Viper holster for Appendix carry, and it will be entering the summer carry rotation. Nice little pistol.