Tanner's Gun Reviews

   By Mike Coviello (Tanner)

Glock 19/Glock 23 Warning

Be careful if you shoot a Glock 19 and a Glock 23. You may end up making a dangerous mistake like shooting a 9mm round of ammunition through your .40 caliber chambered Glock 23 pistol.


Glock 19 Pistol

GLOCK 19 Review GLOCK 26 Review
Exploded View & Parts Trigger Job
Slide Disassembly Trigger Removal
Magazine Disassembly Diagnosing & Repairing
Failure To Extract Extended Slide Lock
Extended Mag Release All Glock Reviews
Glock 19 Pistol
Glock 19 Pistol
Glock 26 Pistol, Ammo & Magazine
Glock 26 Pistol
Glock 17
Glock 17 Pistol
Glock Firing Pin Assembly
Firing Pin

Dangerous Glock Situation?

A Glock 19 is a semi-automatic pistol which shoots 9mm Luger ammunition. A Glock 23 is a semi-automatic pistol which shoots .40 S&W caliber ammunition. Both guns are virtually identical unless you read the designations on each gun. Their magazines also look the same. If you own both guns or shoot both guns, be careful not to get them confused and use the wrong ammunition in the wrong gun. You could end up with a very dangerous situation.

These are pictures of what happens when you fire 9mm Luger Ammo in a .40 caliber Glock 23 pistol. Notice how the casing expanded to fit the .40 caliber chamber (it also shrunk a little). A split can be seen starting to form. A standard 9mm Luger casing and a standard .40 S&W caliber casing are shown next to it for comparison purposes.

Shooting 9mm Luger In A .40 Caliber Pistol? Is That Possible?
Deformed 9mm Luger Case (Left)
Normal 9mm Luger Case (Right)
Deformed 9mm Luger Case (Left)
Normal 9mm Luger Case (Right)
Deformed 9mm Luger Case (Left)
Normal 9mm Luger Case (Middle)
Normal 40 Caliber S&W Case (Right)

Shooting 9mm Luger Ammo In A .40 Caliber Glock 23?

I was at the indoor shooting range yesterday when I struck up a conversation with the guy shooting in the next booth over. His name was Michael. Michael had just purchased two new guns, a G23 and a G27. Both are .40 caliber pistols.

I was shooting 9mm Luger ammunition in my G19. It turned out that my G19 and his G23 were virtually the same gun, only chambered for different ammunition. Offers were extended to shoot each other's guns which lead to a little bit of competition shooting with both of us using the same shooting booth and targets. We would switch off and on. He would shoot, then I would shoot. Both of our guns (and corresponding magazines) rested on the shooting bench adjacent to each other.

When it was Michael's turn to shoot, he picked up his G23, inserted a magazine and fired at the target. A larger than normal ball of fire spit out the front of the barrel and different sounding "bang" was heard. This lead to a jam (almost a stove pipe) in his G23 pistol.

When he removed the spent casing he discovered that it was one of my 9mm rounds. The 9mm Luger casing was badly deformed and expanded (see pictures). It had also started to spit. He had mistakenly picked up my 9mm Glock 19 magazine, inserted it into his .40 caliber G23 and fired it. This could have been disastrous.

Michael immediately field stripped his G23 and inspected the gun and the barrel. Fortunately it looked all right and had no apparent damage. A few shots down range confirmed that he gun was in working order. We then did a little further investigation.

The .40 Caliber Glock 23 Will Shoot 9mm Luger Ammunition (Badly & Dangerously)

We were both amazed and a little shocked to discover that his Glock 23 could shoot my 9mm Luger ammunition. We did not know that it was possible to do so and thought that the Glock Company would have designed safeguards against it. We then inserted my empty Glock 19 magazine into his .40 caliber Glock 23 only to find that it fit like a glove. It snapped into place and functioned just like one of his Glock 23 magazines. The empty magazine locked back the slide and ejected nicely when the magazine release was depressed. You couldn't tell the difference between our two magazines unless you read the inscriptions on them.

At the time we did not think to test his Glock 23 magazine in my Glock 19 pistol, but it would most likely fit. I am assuming that his .40 caliber ammo would not shoot or fit in my .9mm Luger chamber.

Lessons Learned - Don't Mix Up Your Glock 19/23 Ammo & Magazines

If you own both a Glock 19 and a Glock 23 it might be a good idea to color code your magazines as well as your Glocks. It will help avoid a mix-up and a potentially dangerous situation. You can color code your magazines with colored magazine floor plates or Glock magazine floor plate bumpers. You can color code your Glocks with colored slide covers.


Feedback Messages


Interchangeable Glock Magazines

March 21, 2012
What you sated as being a problem with Glocks being that the magazines fit in each others corresponding gun is actually what the majority of us love about Glocks. The magazines are the exact same dimensions and the frames are identical. The fact that I can own a Glock 23 or 22 and simply buy a specific 9mm barrel meant for the Glock 23 and a magazine and now be able to shoot both calibers in the same pistol. Same thing with a Glock 21 being able to shoot 10mm with a 10mm barrel. I think it is one of the huge advantages of a Glock. You could also put a Glock 23 slide on a Glock 19 and shoot .40s&w that way. Glocks are not the only pistol where the .40 cal and 9mm magazines fit in each others gun.

I can't believe the the round actually went off though. That must be a very rare occurrence. The round should've just went further up in the barrel not allowing the firing pin to strike the primer. I guess this is a good lesson to shooters to be sure to have a heightened awareness when operating a firearm of any kind. It is as simple as labeling magazines, guns, maybe a different added grip or colored tape or something if you own both. Or just keeping everything separate.

If Glock were to further their safety measures for this it would have to do with the extractor, barrel or feeding mechanism. Just because you couldn't put a magazine in the gun doesn't mean you couldn't put a round directly in the barrel, so I guess this could happen in any gun which is why it is always advertised to be perfectly sure of the firearms caliber before firing at all times. I simply have never inserted a magazine without looking at the cartridge before inserting, and have never chambered a round before checking for obstructions. I hope your friend will be more careful next time. Happy shooting.


Glock Conversion Kits

March 28, 2012
This is so that conversion kits are possible ex: converting a g19 to shoot 40s



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MIKE COVIELLO is a former aerospace engineer, now Web Designer/SEO Consultant. Hobbies include shooting zombies & reloading ammunition.