Has anyone converted a Glock 21 to a Glock 20 with a barrel change, a magazine change and a recoil spring change? I am also wondering if the new slimmer grip .45 automatic pistol could be converted!

It cant be done. The Glock 21 breech face is too wide for the 10mm case. You can always swap a complete uppper along with a 10mm ejector and you would be set.


g10

Assuming you mean the G36, even Gaston Glock would have a challenge designing a 10mm on a G36 platform as it would likely result in too high a slide velocity for reliable functioning. This was one of the problems encountered with the 40 Super conversion in the G30, at least according to the guys at Lone Wolff Distributors.

But who knows, engineers have been known to do the unthinkable.

KKM does build a conversion barrel built for the 45's hood. They also recommend a new-style LCI extractor. Keep in mind that the slide from a 21 is lighter than the 20's.

I asked about this on glocktalk and was told many have done it. I also received several pm's from those that tried it and never could get it to work reliably.

I never bothered to try with my 1st gen 21.

This post has been edited by remat457: January 3rd 2007 2:01 AM

Glock is supposed to be introducing a slimmer grip .45ACP pistol at the shot show this year. My thought would be that it would be nice to be able to have this grip frame in 10mm, but who knows what the priority would be on a 10mm gun with slimmer grip. If you could buy a complete 10mm slide, spring set, barrel and if the magazine would fit, you could have two slim grip guns in one.

+1

I don't know if it will happen but I would like a slimline 10mm also. The 29 doesn't quite fit me and the 20 is, well, identical to my 21...(not too mention kind of fat)...

I doubt you'll ever see a G36 in 10mm. My guess is there's too little slide mass.

I'm personally aware of several folks who tried the conversion barrel and it wouldn't extract reliably. You'll see posts from folks who claim that they use the conversion barrels and that they're 100%. I think most or all of them are lying. :)

He means the GLOCK 21 SF.

It's a GLOCK 21 with a smaller frame and an ambi magazine release.

I guess my 2 year old G20/21 doesn't exist then.

As with all aftermarket barrels, the 45-10MM conversion barrels have much tighter chambers than stock Glocks. Therefore, like 1911s, some need some tuning to run reliably. I've noted that 'breaking' the edge of the chamber will enhance chambering dramatically. In addition, some have had a few extraction problems due to the light tension the G21's LCI extractor exerts on the 10mm case rim. I have had no extraction problems in almost 6,000rds of 10mm in mine and after tweaking the chamber, it runs very reliably.

BTW, I personally don't know anyone else with a G20 conversion. However, I'm Coloradoglocker and I developed it so I might know a bit more about it than just hearsay.

Here are a couple of new pictures of my G20/21L configured as USPSA G20L "Limited" version, however, as Glock doesn't make a large frame longslide, this isn't USPSA legal. I just liked the look of it for my range and hunting toy.







This post has been edited by CO Steve: January 27th 2007 3:47 PM

I am personally not interested in tuning my 21 to get it to work.

As far as converting the the 21SF I am told that the new ambi-mag release pistols will NOT take the old 21 mags, so I assume that 20 mags are out also.

Would you list the parts you used top make that beaut-it is pretty much what I want.

Unfortunately, the German 6" slide isn't currently available so you'll have to wait for someone to make one.

CO steve,

The breach face was too big I thought. Did you replace the extractor?


g10

The breachface is .050" wider than a G20's, hence the need for a custom 45-10MM barrel from KKM. Note both KKM's and Bar-Sto's barrels have match chambers which are very tight. I've found that the chamber feed more reliabily after I "broke" the edge (slightly rounded the chamber edge from the 2:00 to 10:00 position. In addition, my Jarvis 45 barrel needed the feed ramp to chamber sides (where the ramp and the flat face of the chamber meet) relieved just a bit to help make the feeding reliable too.

Can you guess which one is the Jarvis and which is the stock Glock 45 barrel? NOTE: The Jarvis barrel is before I 'broke' the chamber edges and polished the ramp.



While this is a comparison between my Glock 22 40 chamber and the KKM 45-10MM chamber, you get the idea about how much more support there is. The KKM barrel is after I 'broke' the chamber edges and polished the ramp.



I found that the stock Glock LCI extractor is very reliable in my 6" slide. You can see the claw is angled in the LCI version (right) vs the older flat version (left). You've heard that some with stock slides have extraction issues. Because I don't use the stock slide I can't comment.



The G20 extractor provides no better purchase on the rim of the case than the 45's so I don't recommend it.

My G20/21L has almost 9,000rds of both 45 and 10mm through it with 0, yep ZERO extraction problems. I do find that after about 250 - 300 rounds through either one of my Jarvis 45 or KKM 10MM barrels, I need to swab out the chamber a lick or two to remove the excess carbon to keep the feeding reliable. Those tight match chambers are great for being easy on my brass even with my nuclear loads but they are tight and so need to be kept clean.

BTW, this is the first picture of my G20/21L about 5 minutes after I completed it some 2 years ago. Comparing it to the pictures in my post above shows the changes I've made in that time which include a Dawson FO front sight, chromed slide, rounded trigger guard, and mag well as well as some internal trigger work which REALLY helped.



This post has been edited by CO Steve: February 4th 2007 6:56 PM

Steve,

I didnt releaize that much went into it. This needs to be pinned for awhile. Good picts also. Mind if I save them to my hard drive?

g10

I'd be honored.

Thanks.

g10

I'm still messing with it. I got a Lightning Strike Products magwell for it so I could use my +2 basepads. It weighs about 4oz and with the +2s the balance is great! The magwell forces your hands up high on the grip and that really helps for my long range shooting. The 150yd steel plate is now pretty easy to hit offhand.