I had one mag that would not hold the slide open after the last shot.

This happened in both a XDM 4.5 and 3.8, both in 9mm.
Ammo used was WWB.

SA's customer service was top notch and sent me out a new mag for free, within a week. Awesome!
However, the new mag has the same issue...

Tomorrow I'm heading to the range to test ALL of my mags in BOTH guns. Unfortunately, I was born a poor black child, and will only have WWB at my disposal. I doubt a higher pressured load will make a difference keeping the slide back, after the last round - I think?

Has anyone else experienced this or have any thoughts?

Thanks,
MF

Check the basics first.. thumb not riding on the slide release, not heavily greased, etc.  Other than that, well, it's not unthinkable that you got one bad mag in exchange for another.  Has to happen to someone, sometime.

I remember reading something about them changing followers at one point and that correcting this problem, but I can't remember the details.

Yeah, not the cause...

I have one mag that sometimes does it when racking it by hand slowly. When getting rough with it, or shooting it - it always locks. It would seem that maybe I have a weak mag spring.



The slide lock seems a tad sluggish to me. I wonder if I got lint in there or something when carrying it.... Have to check that.

My old XDm had about 9k through it, and the only problem I had was the slide going forward when a new mag is inserted. My new one doesn't do that. I never had it fail to lock, no marr what I put through it, power wise.

Oh man, do I feel silly... It totally was me resting my hand on the slide stop...

This is something I've never had an issue with on other semi's. This just means practicing placing my strong thumb to the outside of my support hand's thumb, rather than in-line with it. It was kinda awkward at first, as I've pretty much have always held a handgun like the latter explanation... Oh well, I suppose it's not a bad thing, as it will teach me to keep my thumb further away from the slide stop on all handguns.

I was actually surprised how little pressure it took for the slide stop not to engage... I guess it's just because I've never really focused on it before. What a dumby.

MF

Glad you solved your issue!  

A friend had the same issue this weekend using PMC Bronze...slide wouldnt lock back after the last shot was fired.  I was never able to shoot the same ammo to test the issue but it did not happen when using Silver Bear.  Same friend also had his first FTE on the very last shot of the day.  It was 35 and sunny, gun was clean and lubed, and the issues only happened to him.  Hope it was just a fluke!

Check the simple things first, as they say.  Glad you got it straightened out!