View Full Version : Lone Wolf G20 barrel in G21 (gen 4)

08-23-2016, 7:51 PM
Has anyone done this with success? I want to start running 10mm in my G21 and was advised by Lone Wolf CS that I should not run the standard stock length G20 barrel in my G21. It is my understanding that the G20 barrel SHOULD work, but obviously they can't 100% tell me "yeah go ahead and do it". I was looking to get the barrel, and then the extractor. It seems like for gen 4's, both the G20 and G21 use the same exact recoil spring.

Anyone with any more advice would be great, I know KKM makes a conversion but I can't seem to find one.

Bill Steele
08-24-2016, 1:24 AM
I would recommend buying a complete Gen 4 slide assembly (along with as many 10mm magazines as you need). The reason I prefer this route is the G20 slide is heavier (less material milled off inside). This added weight helps slow down the slide when shooting the hotter 10mm.

You are correct that the stock RSA is the same in the G20/G21. In my opinion the stock G20 RSA is under sprung. When I run my hottest 10mm loads (anything over about 1250fps with a 180gr projectile), the slide will start battering the frame up by the front slide lug unless I run a heavier RSA. You can see where this impact occurs by just mounting the empty slide on the gun and running it all the way back until it stops. Where the front of the slide stops against the frame is where the battering will occur.

I do know guys that run a 10mm conversion barrel in their G21 slides. Depending on how hot they like to run, most run heavy RSAs and some need to double up on the magazine springs to allow the magazine to keep up with the slide velocity. There used to be a lot of companies that made a 10mm conversion barrel for the G21, not as many any more. There might be a reason. ;)

PS - It just dawned on me that you might have been asking about running a stock g20 barrel (dimensionally) in a G21 slide. The breech face in the G21 slide is wider, so the G20 barrel hood has gaps on either side where is sits in the slide. The gaps run down both sides of the hood where they sit in the slide. The barrel will lock up in the G21 slide, but those gaps on either side might present function problems at some point. I would think that slop would present at least wear problems down the road. There had to be a reason the barrel guys did a conversion barrel originally, so the hood would fit in the wider G21 slide.

Bill Steele
08-24-2016, 6:57 AM
Here are a few pictures of stock G20 barrel in a G21 slide, hence why they have conversion barrels.

http://i228.photobucket.com/albums/ee169/Bill_Steele/2016-08-24%2008.39.41.jpg (http://s228.photobucket.com/user/Bill_Steele/media/2016-08-24%2008.39.41.jpg.html)

http://i228.photobucket.com/albums/ee169/Bill_Steele/2016-08-24%2008.41.41-4.jpg (http://s228.photobucket.com/user/Bill_Steele/media/2016-08-24%2008.41.41-4.jpg.html)

Here is the way the G21 barrel fits in the G21 slide.

http://i228.photobucket.com/albums/ee169/Bill_Steele/2016-08-24%2008.43.02.jpg (http://s228.photobucket.com/user/Bill_Steele/media/2016-08-24%2008.43.02.jpg.html)

08-25-2016, 3:03 AM
Thank you for the info sir!

08-25-2016, 8:31 PM
Complete slide swap or storm lake makes a 45-10mm conversion barrel. Choose.

08-26-2016, 4:01 PM
I do it, and have no problems with it. I sat down and shot a whole bunch of rounds off of a rest, with a KKM 6" G20 barrel, in my G21 slide, to see if it would shoot well enough for me to be happy.

I then shot several groups of the same ammo off the same rest in the same conditions with the same frame and barrel, but with my G20 slide, and there was no difference in group size.

It's not ideal, but it's cheap. I have not shot more than a couple hundred rounds of 10mm this way, but have had zero trouble and zero odd wear yet.