Can this Glock 21 magazine be modified for 10mm?

[Pablo]

The magazine holds 31 rounds of 10mm.

[sqlbullet]

Capacity depends on how much you squeezed the springs.  Before I did anything, my held 33 rounds, but the spring would hang up when it entered the Glock 20 body.

After I removed the lip with a file and bent the springs, mine hold 32.

[Pablo]

Good to know. I obviously haven't shot mine yet. Nice option for the price.

[Pablo]

Capacity depends on how much you squeezed the springs.  Before I did anything, my held 33 rounds, but the spring would hang up when it entered the Glock 20 body.

After I removed the lip with a file and bent the springs, mine hold 32.

Wait. Are we talking apples vs. oranges? What lip? Why mod the spring? I THINK you are talking about the mag extender. I'm talking about a straight up Glock 21 imitation mag, modified for 10mm.

[sqlbullet]

Yeah, apples to oranges.

I used G20 mags with the extender and got 32.

[Captain_Witness]

https://www.classicfirearms.com/1911-45-caliber-28rd-drum-magazine

[Pablo]

Can this Glock 21 magazine be modified for 10mm?  - YES

Finally got the Glock 20SF-L to the range. The full extended magazine popped in perfectly. The balance seemed natural. And with 30 rounds of 10mm on a longslide not super heavy in hand. The magazine fed just fine.  (I was fighting with the slide jamming back, so no rapid fire).

All I did was slightly tweak the feed lips in.