Can you convert a Glock 20 to .45ACP?

[millercreek]

I know you can go to .40 with just a barrel but could you change to .45 with a barrel and a magazine?

[Silvanus]

As far as I know a simple barrel change is not enough.

Quick google search for "glock caliber conversion chart"

http://www.glockfaq.com/gunsmithing.htm

[AZGlock13]

No. Just changing the barrel and the mag won't do it. The breach face and the muzzle barrel hole on the G20's slide is too small to accommodate a .45ACP case head and a .45ACP diameter barrel. Same reason why you can't shoot .40S&W out of a slide made for 9mm. Now if you were to find a complete G21 upper (full G21 slide and barrel assembly), then you could use it with your G20 frame/receiver (along with a G21 mag(s)). The problem with finding complete Glock uppers, is they're hard to find (got to be on the look out for one on GlockTalk's gun accessories classifieds forum section) and when you do find someone selling one, you can usually buy a complete used Glock (in this case, a good used G21) for just a little bit more money (thus not making it worth it most of the time (however, uppers don't require shipping to an FFL, so you do save some FFL transfer fee money there)).

[Alleykat]

The G20's barrel is the same o.d. as a G21's barrel. The problem is with the extractor and breechface cut.

[AZGlock13]

Alleykat, You're right. I don't have my G20 any more (traded it off last year, which I'm still regretting), so I couldn't compare it with my G21. I do have both the G29 and the G30. I took the two apart and put the G30 barrel through the muzzle barrel hole on the G29's slide (inserting the barrel from the outside into the outside of the muzzle barrel hole) and sure enough it fits perfectly like the G29 barrel does (same clearance). I just always assumed that the outside barrel diameter on both the G29 and G20 barrels were slightly smaller than that of the G30 and G21 barrels. Sorry for the bad info I gave.:o

However, I did find as I thought, you can't put the G30 barrel into the G29's slide, due to the G30's barrel chamber hood is too wide (at the breech face end) to fit into the G29's slide's top breech ejection cut-out (top cut-out on slide that receives and locks in the barrel's chamber hood). You can put the G29 barrel into the G30 slide, but you have some gap on both sides of the barrel's chamber hood (at the breech face end) and the slide.