Due to the different shapes of the baseplates, it's difficult to come up with a way to measure them that is comparable. Here are a few side-by-side/stacked photos, maybe that'll be more help:

 

Th

Due to the different shapes of the baseplates, it's difficult to come up with a way to measure them that is comparable. Here are a few side-by-side/stacked photos, maybe that'll be more help:

View attachment 641250

View attachment 641252

View attachment 641254

thank you!

 

Appreciate the OP's posting as well as the great response with images. I just converted one of my Glock 26 mags to a 12-round OEM. I love it. The conversion was only $11.00 so why not?
But for me to get a Glock 19 mag and x-grip is something I'm considering as well.

 

I can say this, the Magpul PMAG Glock 12 GL9 9mm 12-Round Magazine is better than the OEM option, and is shorter than the OEM extension.

https://gunmagwarehouse.com/magpul-pmag-12-gl9-glock-26-9mm-12-round-polymer-magazine.html

VERY reliable, easy to clean and disassemble. It's what I used when I carried a G26.

 

I agree. I really like the Magpul 12rd mag, it gives a very comfortable grip. The 20rd makes a nice reload.