Keltec sub2000 mag question

[juffin]

I have a somewhat unusual question (I'm relatively new to this all). I have a keltec sub2000 that can take G17 mags. The one I have came with a 10-round (because massachusetts) square notch mag.

Its there a functional difference between square and "U" notch mags? Like, if the gun takes square-notch mags, can it also take U-shape ones?

 

[F2386]

It takes all G17 mags regards of U or square notch. Modify the grip and you can even use G19 mags. Bet might be able to use G26 mags if you try hard enough.

 

[juffin]

Thank you!