Magazine won't stay engaged

[worldtraveler119]

I have a Sig P238 with standard 6 round magazines and everything works fine. I recently bought a couple extended 7 round magazines (stamped Sig on the bottom) on the interweb and they won't stay in the pistol when i place them in the mag well. Anyone have an idea what is going on?

 

[MikeJackmin]

First thing (if you are not doing it already) is to insert the mag with the slide locked open.

If it still fails, then the likely culprit is the little notch on the side of the magazine that engages the magazine catch in the pistol. It might need to be filed just a hair higher. This is likely to be a very small amount, so go slow.

 

[JTQ]

What MikeJackmin doesn't continue with is if the mag inserts fine with the slide back, but not with the slide forward, it is because there is not enough space in the tube for the spring to compress in its' current status (there are too many rounds to comfortably fit in a tube that size).

You can load and unload the mag dozens of times to get the spring to take a set, or load it up and let is sit for a few days to see if it becomes easier to seat. Chances are good you could seat it now, you'd just need more force than appears prudent to you at this time.