9mm Out Of A Glock 20/21?

[Gun1]

I have a number of Glocks 20 and 21s. Lately though I've been thinking of trying out 9mm ofr the range. I know Glocks in 40 S&W can be converted into 9mm but can a large frame Glock like a 20 or 21 be converted into 9mm? And will Glock 17 magazines actually work in a Glock 20/21? And how about a Glock 30/29?

 

[Dan-O]

Short answer is no

 

[Gun1]

How about the long answer?

 

[crestoncowboy]

The mags wont work from a 17 in a 20. Many people shoot 40 through the glock 20. Some use a conversion barrel. 9mm rounds will feed through a Glock 22 mag (.40) well enough for range use (I've never had a failure but Id still use 17 mags for real use) in my experience so I'd assume 9mm will feed from the Glock 20 magazine . I know there used to be conversion barrels and recoil springs (that's a heavy slide) for 9mm in a Glock 20.

I have little experience with the Glock 21 but obviously you would have to use 20 mags to feed 9mm into the conversion barrel if one is made.

 

[jmr40]

Go over to Glocktalk and ask there. I never joined, but used to hang out there some. I'm thinking there is a way to make it work, but could be wrong. And I don't know how if it can be done. I do know there are a lot of conversion barrels available to convert Glocks to fire other cartridges.

But the simplest answer is to simply buy a 9mm Glock. Doing a conversion won't be much cheaper. Used G17's can be picked up for $300-$350 and you can't wear one out. If you get one with issues send it back to Glock and they'll make it like new at no cost to you.

 

[ugaarguy]

How about the long answer?

Lone Wolf used to sell a G20 to 9mm bbl. You had to run a lighter recoil spring and use +P ammo to get it to run semi-reliably. Running +P 9mm kind of defeats the purpose of running 9mm. Lone Wolf has quit selling that particular conversion bbl. The extractor and ejector on the G21 won't work with 9mm at all, since the .45 ACP case head is so much larger. You can convert a .40 S&W or .357 SIG Glock to 9mm. You can also convert a 10mm Glock to .40 S&W, since the .40 is just a short 10mm, and it has enough bullet weight and velocity to move the big, heavy 10mm slide. If you already have .40 Glock, then the $140 conversion bbl makes sense. If you don't, buying a used .40 Glock and the new conversion bbl gets you pretty close to the cost of a new 9mm Glock, even with the .40 S&W Glocks being dirt cheap right now.

 

[Dan-O]

You’d have to modify the feed lips on the 10mm mags. It won’t work period in .45 mags.

Like another one said, Lonewolf used to make a conversion barrel for 10 to 9. There were too many dumbasses that didn’t follow their direction on how to make it work and they got tired of people asking for refunds. They also used to make a 10 to 38 super conversion. Guess what, the feed lips had to be modified on these too. Guess what, they don’t make it anymore for a reason.

Theres my long answer.

 

[Pat Riot]

I believe it would be more cost effective to just buy a used Glock in 9mm.

 

[JTQ]

I believe it would be more cost effective to just buy a used Glock in 9mm.

Probably also cheaper to buy a new Glock than trying to modify a G20/21 to shoot 9mm.

 

[crestoncowboy]

You’d have to modify the feed lips on the 10mm mags.

Appears so. I have fired 10s of thousands of 9mm in the 40 mags. But it does look like the front of the lips is wider on the 10mm. Both of these mags are fully loaded with 10/40 with a 9mm on top. The rear of the feed lips is the same width. The front is definitely wider on the 10mm. Same with all of my mags

I'd either use .40 in the Glock 20 or I would buy a cheap used gen 3 9mm