Not sure which product you are using, I've used the Mag Packer with no trouble.

https://www.amazon.com/dp/B0048KDL3G/ref=cm_sw_r_cp_apa_a4rFybSH6QFZA

With the Mag Packer, the open end of mag goes in first.

 

Yes, that is the one I am using. The bullets coming out of the mag bothers me. Don't know how it can happen.

 

You say you install the mag with the open end up. Does this mean the top cartridge is visible when the mag is installed? That might just explain how the cartridge comes out, it is being knocked out. The mag needs to be inserted so the open end is not visible.

 

The mag needs to be inserted so the open end is not visible.

+1
I agree with Major Tom. Open end down, Butt Plate up.

 

Had the same thing happen when trying to carry P938 mags in a nylon mag pouch with Velcro closure, closed snug or loose didn't matter. pull the mag out of the holder and two or three rounds would be left behind.

The problem is that the rounds seem to *want* to come out of the magazine with this gun, so if anything can bump or push against the top round, it'll tend to come out. I tried putting some foam in the bottom of the mag pouch to sort of secure the round to prevent it moving forward - no help.

This magazine pouch works:

https://www.amazon.com/BLACKHAWK-Single-Stack-Carbon-Finish/dp/B002E6V0UW/ref=sr_1_3?ie=UTF8&qid=1484599274&sr=8-3&keywords=cf%2Bsingle%2Brow%2Bmag%2Bcase&th=1