G20 or g21?
- Thread starter Smcx
- Start date
scuba_cowboy
CGN Regular
- Location
- Calgary, Alberta
G20 can have conversion barrels for both 45 ACP and 40 S&W.
I don't believe there is a .22 conversion kit for the large frame Glocks.
G20 can fire .40 with stock 10mm barrel as the extractor holds the case in place for the firing pin to engage, but the accuracy goes to crap as there is bit of a space for the bullet to cross before rifling begins.
As for 9mm conversion barrels in a large frame Glock, again don't think they exist, as the large frame recoil springs are to stiff for a 9mm to cycle properly- maybe with an adjustable recoil spring?
You can make a G21 work with 10mm & .40 conversion barrels, but G21 slide is quite a bit lighter than a G20 slide and might not stand up to full power 10mm loads (G20 & G21 slides are identical in sizing but the G21 has quite a bit more metal removed along the slide forward of the ejection port so it is about 1.4 ounces lighter than a G20 slide). The locking blocks and recoil springs are the same part numbers for the G20 & G21, the extractors are listed as different, but in my experience with Gen4s will work with either.
I have personally done all of these conversions with my past G20 & G21 and all combos function fine. When using the .40 conversion barrel in the large frames you are better off using a Gen 3 recoil spring as it is a bit less stiff, and cycles the .40 ammo better than a Gen 4 spring (you can get a spring adapter bushing from IGB to use a Gen 3 spring in a Gen 4).
I don't believe there is a .22 conversion kit for the large frame Glocks.
G20 can fire .40 with stock 10mm barrel as the extractor holds the case in place for the firing pin to engage, but the accuracy goes to crap as there is bit of a space for the bullet to cross before rifling begins.
As for 9mm conversion barrels in a large frame Glock, again don't think they exist, as the large frame recoil springs are to stiff for a 9mm to cycle properly- maybe with an adjustable recoil spring?
You can make a G21 work with 10mm & .40 conversion barrels, but G21 slide is quite a bit lighter than a G20 slide and might not stand up to full power 10mm loads (G20 & G21 slides are identical in sizing but the G21 has quite a bit more metal removed along the slide forward of the ejection port so it is about 1.4 ounces lighter than a G20 slide). The locking blocks and recoil springs are the same part numbers for the G20 & G21, the extractors are listed as different, but in my experience with Gen4s will work with either.
I have personally done all of these conversions with my past G20 & G21 and all combos function fine. When using the .40 conversion barrel in the large frames you are better off using a Gen 3 recoil spring as it is a bit less stiff, and cycles the .40 ammo better than a Gen 4 spring (you can get a spring adapter bushing from IGB to use a Gen 3 spring in a Gen 4).
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- Location
- The Orion Arm
I have a 4th gen G20 with a Lone Wolf .40 conversion barrel. Love it and it even takes the same mags as the 10mm. Next need to get a .45 conversion barrel and a few mags.
KotKotofeich
CGN Ultra frequent flyer
- Location
- Ottawa Valley
G20 and G21 are essentially the same so it doesn't matter what you start with.
I started with a G21 and currently have the .22 conversion (full upper) and a 400cb (barrel). There's a 460 rowland conversion (you need a barrel with a muzzle brake or a barrel and stiffer springs in the magazines with posible damage to the frame in either case from the recoil)
I will at some point buy a full upper off a G20 and it fits the G21 lower, then you can put whatever barrel conversions you want on it. (40sw and 357sig)
There's also a 50gi full upper conversion that fits either.
I started with a G21 and currently have the .22 conversion (full upper) and a 400cb (barrel). There's a 460 rowland conversion (you need a barrel with a muzzle brake or a barrel and stiffer springs in the magazines with posible damage to the frame in either case from the recoil)
I will at some point buy a full upper off a G20 and it fits the G21 lower, then you can put whatever barrel conversions you want on it. (40sw and 357sig)
There's also a 50gi full upper conversion that fits either.
