Glock 21 shooting 10mm


Well-Known Member
Nov 10, 2013
I've seen a few different YouTube videos that guys are swapping out the factory 21 45 acp barrel, guide rod/spring, extractor and magazines to 10mm. The result is now your 21 is essentially a 20 10mm.

My question is will a Glock 20 replacement barrel work say Lone Wolf 6"? Also what pound recoil spring would be best 20# or 22#? Had anyone that done a similar conversion run into any reliability and or feeding issues?
Keep with factory unless you want to start to wear the slide wear the muzzle of the barrel rest.

But I know that's hard to find in 10mm. So if you want to use lone wolf. Try to stick with the factory length.
The stock glock 20 spring will have the better function overall but a 22lb ismi spring will be better for loads that run the spectrum.
I would think the breach face would be too wide.
Good observation.

Yes this ^ is correct. You need a lone wolf slide or factory 20 slide too.

A lot of the "success" stories are from when the "conversion" barrels when that was happening. So when I'd get them for "reliability" issues I'd have to tell them glock wasn't going to be doing anything to help them, and buy a 20 slide and slide parts kit. Cheaper way to get parts is send a oem stripper slide to glock after buying the night sights from them and it will come back with all parts put in. Sights cost like $20 something.
I would not recommend taking on a modification like this unless you are a expert gunsmith with lots of experience with Glock's because there are many pitfalls that you can encounter that will be difficult to deal with.

The manufacture has many hours testing and developing there pistols and your best bet in my opinion is to sell one and buy what you want (Or keep both)

The 10 mm is a powerful round and has to be set up right to give the performance it was intended to without harm to the firearm.

We are all do it yourself motivated, but sometimes it is best to error on the side of caution.

Just my opinion

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