9MM Out Of A 20 Mag

It's not the OAL of the 9mm round, it's the width of the feed lips. Wouldn't recommend it.

deathmigraine said:

Sort of a Glock question
I am building up a 9mm AR15
I am making a lower
I was going to use Glock 17 pattern for the mag well
But I sold my Glock 20 and have mags left over
I got to thinking , 9mm feeds out of my Glock 22 mags
If I use Glock 20 mags I could load the 160 gr cast bullets slightly long

Your thoughts ?

Thanks
John

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Will Glock 20 mags fit in a Glock 17 magwell?

No. And a Glock 20/21 will not hang onto Glock 17/22 mags either .

mc1911 said:

Will Glock 20 mags fit in a Glock 17 magwell?

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Nope!

SixG17s said:

No. And a Glock 20/21 will not hang onto Glock 17/22 mags either .

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You beat me to it.

no and no, .45 and 10mm mags are large frame mags, all else are medium frame mags.
FWIW I've beat the feed lips on .45 Glock mags to reliably feed 10mm so yea, theoretically you could 'tune' 10mm mags for 9mm but you'd have to build you rifle off a large frame Glock mag lower. You'd spend more on the lower than new 9mm mags. And no one would want it if you tried to sell it.