Glock 20 SF or 20 Gen 4?

[CaliforniaDreamin]

[Whatisthis?]

Yes, you can shoot .40 from a Glock 20 Gen 4 stock barrel (The only changes were the RSA, magazine release, and grip texture... I think a couple internal trigger parts were changed too, but it doesn't effect shooting .40 out of it).

You can never go up in size... so something, like a slide, that is made for a barrel that shoots .40" diameter will not be able to shoot .45" diameter stuff with a barrel change. So, yes, you would need a complete Gen 4 Glock 21 slide.

The RSA on a Gen 4 significantly reduces recoil IMO. I bought a gen 4 Glock 20 when I already had a gen 3, and ended up selling the Gen 4 to a friend... and I shouldn't have sold it as I like it more than my Gen 3 now.

KKM barrels are great, American made products (USA!). It's really not necessary unless 1) you want to reload as it will probably increase case life 2) You want to shoot lead out of it (which still isn't completely necessary but nice to have).

[JWHuey]

I just sold my full size gen 3 20 & bought a gen 4.

The grip with no backstrap on the gen 4 is almost identical to the gen 3 SF, & I prefer the texture as well. I haven't shot .40 through mine (I know I can), as I prefer to use PPU 10mm HP ammo for plinking, which is close to the same cost as .40 & ballistics are the same as well.

[003]

There is much misformation going around about being able to shoot .40 caliber in a 10MM barrel. While it is possible, and you may "get away with it", it is not safe, and most definately not a good practice.

The .40 and 10mm, headspace on the cartridge mouth. While you can load a .40 into a 10mm chamber, firing it would be unsafe. The extractor is the only thing holding the .40 cal case against the breech face. Don't do it.

Do a bit of on line research. Specifically, google gun writer Patrick Sweeney and read what he has to say.

[TheExiled]

You can get a 10mm and .40 barrel for your G21, you cannot get a .45 barrel for your G20. You would have to swap the entire slide instead of just barrel and mags. Gen 4 frames only work with gen 4 slides.

If ease of interchangeability is what youre after, go Gen3. I have a Gen3 G20 and Gen4 G29, the G4 G29 has the same or less recoil than my G3 G20, I think due to the new recoil spring

[Bill Steele]

There is much misformation going around about being able to shoot .40 caliber in a 10MM barrel. While it is possible, and you may "get away with it", it is not safe, and most definately not a good practice.

The .40 and 10mm, headspace on the cartridge mouth. While you can load a .40 into a 10mm chamber, firing it would be unsafe. The extractor is the only thing holding the .40 cal case against the breech face. Don't do it.

Do a bit of on line research. Specifically, google gun writer Patrick Sweeney and read what he has to say.

Talk about misinformation.

Every article I have ever seen that cites shooting 40 in 10mm as unsafe/bad practice is concerning 1911 pattern guns. The problem with this style gun is it lacks a positive firing pin stop. This is a potential issue if the round were to slip the extractor (or more likely the extractor claw broke), the 40 case would slide down into the chamber and headspace on the case mouth. Then with the firing pin able to reach the primer, when the trigger was pulled the space between the breech face and the case head could be filled by the case, likely leading to a case head failure. I agree with this risk, in that pattern gun, even though I would not classify it as a life and limb kind of risk. It is jarring though when the magazine comes flying out the bottom of the gun...

In the case of the Glock, the gun has a very stout and effective extractor and even if it broke and the case slid down into the chamber, the firing pin has a positive stop and won't reach the primer, so the worst case is a "click" misfire. The failure would be obvious to the most casual observer as the gun would not extract the round sitting down in the chamber.

A misfire is only unsafe if you are using the gun for self defense. If you are using 40's in a 10mm gun for defense, maybe you are a candidate for a Darwin award anyway.

For anyone not understanding the above explanation, just stick to 10mm in your 10mm guns and be happy.

I think all the questions on the caliber mix and match possibilities for the Gen 3 and Gen 4 have already been covered above.

[Baboosh]

Glock 20 Gen 4 Full FDE

[TheExiled]

Glock 20 Gen 4 Full FDE

[Clutch-n-Throttle]

You can get a 10mm and .40 barrel for your G21, you cannot get a .45 barrel for your G20...

I have a G21 Gen 4. Where can I get those 10mm and/or 40 cal barrels for my G21?

[Bill Steele]

I have a G21 Gen 4. Where can I get those 10mm and/or 40 cal barrels for my G21?

Here you go: http://www.glockmeister.com/Storm-La...2D10MMC%2D460/


You will want a 10mm magazine as well.

[003]

KKM makes excellent conversion barrels

http://www.kkmprecision.com/

[Clutch-n-Throttle]

Here you go: http://www.glockmeister.com/Storm-La...2D10MMC%2D460/


You will want a 10mm magazine as well.

KKM makes excellent conversion barrels

http://www.kkmprecision.com/

Thx guys.

[Oceanbob]

Talk about misinformation.

Every article I have ever seen that cites shooting 40 in 10mm as unsafe/bad practice is concerning 1911 pattern guns. The problem with this style gun is it lacks a positive firing pin stop. This is a potential issue if the round were to slip the extractor (or more likely the extractor claw broke), the 40 case would slide down into the chamber and headspace on the case mouth. Then with the firing pin able to reach the primer, when the trigger was pulled the space between the breech face and the case head could be filled by the case, likely leading to a case head failure. I agree with this risk, in that pattern gun, even though I would not classify it as a life and limb kind of risk. It is jarring though when the magazine comes flying out the bottom of the gun...

In the case of the Glock, the gun has a very stout and effective extractor and even if it broke and the case slid down into the chamber, the firing pin has a positive stop and won't reach the primer, so the worst case is a "click" misfire. The failure would be obvious to the most casual observer as the gun would not extract the round sitting down in the chamber.

A misfire is only unsafe if you are using the gun for self defense. If you are using 40's in a 10mm gun for defense, maybe you are a candidate for a Darwin award anyway.

For anyone not understanding the above explanation, just stick to 10mm in your 10mm guns and be happy.

I think all the questions on the caliber mix and match possibilities for the Gen 3 and Gen 4 have already been covered above.

This ^^^^^^^

Glocks only. I've run over 2000 rounds of .40 thru my various Glock 20s. No issues and nothing dangerous can happen. Glocks only.!

As Bill mentioned, this subject has been covered long ago.

[003]

I find it interesting that some members here just refuse to accept that shooting .40 cal in a 10MM is a bad idea. Just because it can be done does not mean it is a good idea or safe to do so in the long run. While some here may feel it is a “settled” issue that is not the case at all. While we can all do an internet search and find an article to two that will support just about any position we want to take on any issue, I have never read or seen anything published by an ammunition or firearm manufacture that would endorse the use of .40 cal ammunition in a 10MM stock pistol, (Glock included). While I really do not want to create friction, or fuel hard feelings, I challenge anyone to provide real evidence that “competent”, professional authority endorse the idea.

[Bill Steele]

I find it interesting that some members here just refuse to accept that shooting .40 cal in a 10MM is a bad idea. Just because it can be done does not mean it is a good idea or safe to do so in the long run. While some here may feel it is a “settled” issue that is not the case at all. While we can all do an internet search and find an article to two that will support just about any position we want to take on any issue, I have never read or seen anything published by an ammunition or firearm manufacture that would endorse the use of .40 cal ammunition in a 10MM stock pistol, (Glock included). While I really do not want to create friction, or fuel hard feelings, I challenge anyone to provide real evidence that “competent”, professional authority endorse the idea.

Let's try it this way. You explain what can go wrong with shooting 40 out of a Glock 10mm chamber, and I will see if I can explain technically why it is not a concern.

Otherwise it is just FUD.