I had a magazine failure today with my 9mm Dan Wesson Guardian using the factory magazine (I believe to be made by Metalform w/ steel base plate). I was using it as a carry magazine because I like the low profile floor plate. The gun is bobtailed so I don't like magazines that stick out another 1/4" like the Wilson 9mm mags do.

Tonight the magazine repeatedly failed to lock the slide back, continually got stuck in the gun (had to pry it out), and cased the slide to drag making the gun fail to go into battery.  Never had a problem with this mag before or a similar issue with any 1911 mag. Had been loaded for about a year which is a relatively short amount of time, all things considered.

Switched to Wilson mags and they ran perfectly.

So now I'm looking for a few replacement low profile 9 round mags but no longer trust Metaform/Dan Wesson mags. I carry a Wilson for a spare mag on my belt for the extra round but prefer something more compact to EDC in the gun.

I had very good luck with metalforms when I had a 9. If you want to try another flush fit brand checkmate is good too. Might want to check also if you can replace the big Wilson pad with the thin low profile metal pads they sell

Time for some replacement spring try some Wolff +10%. Wolff springs always fixed my 47d issues with slide lock not working.

I had a few thousand (total) rounds on 7, 10 rd Metalform mags, never an issue.

The follower (stamped sheet metal I'm guessing) jumped over the slide stop lug.

Yep. Follower needs to be tuned. I used to shoot a dozen 9 round 9mm Metalforms and most of them would let the follower jump the lobe on the slide stop.

You have to bend it out a bit.

Mec Gar mags. I bought a ton of them for $6 each when the seller was retiring and going out of business, they work great. Mec Gar makes mags for a lot of top firearm companies.

The last MF mag I had had the follower snap in two, was not impressed.

Metalform 9 round and Wilson 10 rounds are my go to 9mm magazines. The only ones I have really had problems with were the Dan Wesson 10 round Checkmates, they wouldn't feed my Valor at all. Switched to the Wilson's and it was good to go

My DW Specialist in 9 has been flawless with Wilson 10 rounders.

I wish Wilson would make a 9 round flush fit ETM.