View Full Version : 40 S&W though an unmodified Glock 20 10mm
titsonritz
09-23-15, 18:34
I have seen and heard folks running 40 S&W down their 10mm barrels and was wondering if any one here has experience good or bad doing it?
http://www.thetruthaboutguns.com/2015/06/jeremy-s/40-in-a-10mm-glock/
I have done it with mine just to try it and it worked fine. It was actually unremarkable as it fired just like any other pistol. I don't remember exactly how many rounds I fired but it was less than a full mag.
That said, I wouldn't make a habit out of it.
Pistol ammunition headspaces off the case mouth. Short brass can cause light primer hits.
I agree with Ryno. I would not make a habit out of it either.
Exiledviking
09-23-15, 21:24
I ran a KKM conversion .40 S&W barrel in my G 20SF successfully with no other changes to the pistol. Softest shooting .40 S&W I have fired.
I ran a KKM conversion .40 S&W barrel in my G 20SF successfully with no other changes to the pistol. Softest shooting .40 S&W I have fired.
That's not what the OP is asking. He wondering if anyone has shot 40 S&W through a bone stock G20, with the 10mm barrel.
What you're doing is exactly what the conversion barrel was intended for.
Exiledviking
09-23-15, 21:36
Ah. Wouldn't recommend that. Certainly no need to do that with readily available conversion barrels.
titsonritz
09-23-15, 22:24
Pistol ammunition headspaces off the case mouth. Short brass can cause light primer hits.
I agree with Ryno. I would not make a habit out of it either.
The 40 S&W ammo is headspaced via the extractor creating an extended freebore.
titsonritz
09-23-15, 22:33
I ran a KKM conversion .40 S&W barrel in my G 20SF successfully with no other changes to the pistol. Softest shooting .40 S&W I have fired.
Ah. Wouldn't recommend that. Certainly no need to do that with readily available conversion barrels.
I realize that would be the best way to go if I planned a steady diet of 40S&W through a G20 but I have no such plans so I won't be buy a new barrel, but being able to shoot both rounds safely does have its attraction.
The 40 S&W ammo is headspaced via the extractor creating an extended freebore.
The pistol may or may not function when headspaced via the extractor, but it is dangerous. The problem is that if the cartridge feeds ahead of the extractor and the firing pin is long enough to ignite the primer, you could have a ruptured primer and be exposed to hot gas. 10mm brass is 0.001" thicker at the case web than .40 S&W brass, which allows for additional expansion and offers another opportunity for case rupture and gas to escape.
An exaggerated example of shooting ammunition not designed for the chamber is shooting .308 ammunition through a M1 Garand chambered in 30-06. You might get away with it several times, but eventually it will bite you.
The pistol may or may not function when headspaced via the extractor, but it is dangerous. The problem is that if the cartridge feeds ahead of the extractor and the firing pin is long enough to ignite the primer, you could have a ruptured primer and be exposed to hot gas. 10mm brass is 0.001" thicker at the case web than .40 S&W brass, which allows for additional expansion and offers another opportunity for case rupture and gas to escape.
An exaggerated example of shooting ammunition not designed for the chamber is shooting .308 ammunition through a M1 Garand chambered in 30-06. You might get away with it several times, but eventually it will bite you.
Agreed
It's never a good idea to shoot a gun a with ammo it was not designed for. Couple that with the lack of case support with the OEM barrels you're likely asking for trouble.
I ultimately went with a 6" SL barrel since I needed the extra length for hunting. I found it to be much easier on the brass too.
(Don't misconstrue that to mean that it's ok to shoot the wrong ammo in an aftermarket barrel either.)
Howdy,
I tried this with my G20 back in 1993.
I thought it was a bad idea back then and still do.
Paul
P.S. Back in '93 there wasn't any conversion or aftermarket barrels.
Folks should read an article all the way through before commenting on it.
1) The article is a first hand report of two shooters each running at least ten thousand rounds of 40 in an unmodified 10mm Glock without issue. It also has a second hand report of a third shooter doing the same
2) The extra leade reduces chamber pressure. It has the additional benefit of making the pressure curve less sharp and the 40 S&W has one of the sharpest pressure curves among pistol rounds
3) The article points out that the Glock firing pin has a physical block. It cannot over travel and cause primer piercings if the case is not held against the bolt face. The Glock extractor is large and strong enough to hold the case at against the bolt face
The one mistake the author makes is identifying excessive head space as a source of kabooms. Firing a 40 in 10mm chamber is the very definition of excessive head space
The article was interesting. My concern is with people trying this in a S&W 1076 or another handgun based on the results with a Glock 20.
Has this experiment been conducted with any other 10mm pistol made by a different firearm manufacturer? Anyone who owns a 10mm other than a Glock want to try this?
The fact that the author states that he feels it's safer to shoot a .40 through the 10mm than it is to shoot a .40 through a .40 or a 10mm through a 10mm, then goes on to tell everyone NOT do it, makes him an idiot in my book.
He also states the rounds slide up the breach face & slip under the extractor, which I agree with... under normal conditions. The problem with that being with the .40 cases are quite a bit shorter than the 10mm. The cases can be shifted forward in the magazine thus not allowing a fluid transfer under the extractor. The feeding can be erratic & in some cases the extractor will snap over the rim if the cases are far enough forward in the mag. If you reload, the excessive wear on the rims isn't a good thing either.
I understand that hand cycling isn't a 1:1 comparison to live fire but grab your G20 & load it with .40 snap caps. You'll see what I mean.
I do agree that it works, as I've tried it first hand, but I still wouldn't make a habit out of it.
Howdy,
Folks should read an article all the way through before commenting on it.
1) The article is a first hand report of two shooters each running at least ten thousand rounds of 40 in an unmodified 10mm Glock without issue. It also has a second hand report of a third shooter doing the same
2) The extra leade reduces chamber pressure. It has the additional benefit of making the pressure curve less sharp and the 40 S&W has one of the sharpest pressure curves among pistol rounds
3) The article points out that the Glock firing pin has a physical block. It cannot over travel and cause primer piercings if the case is not held against the bolt face. The Glock extractor is large and strong enough to hold the case at against the bolt face
The one mistake the author makes is identifying excessive head space as a source of kabooms. Firing a 40 in 10mm chamber is the very definition of excessive head space
I was trying to figure out how to post a response without sounding like a jerk but that's just not my style.
Anywho.......
Gee, as a person that has been shooting 10mm for almost 30 years and has sent +30,000 rounds downrange, and has been shooting .40S&W for over 20 years and has sent +30,000 rounds downrange, has been reloading 10mm and .40S&W for over 20 years and have tried the .40S&W in a 10mm barrel trick I will have to call BULLSHITTE on the above mentioned stories.
I also feel sorry for anyone that is gullible enough to believe the above mentioned stories.
Paul
Stengun, you think the author is lying to us? You don't think he actually shoots 40 S&W through his 10mm Glock? You don't think I've got enough technical knowledge and experience under my belt to find the author's analysis plausible?
Just checking......
I know Glock absolutely recommendes against firing the 40 s&w in the 10mm chamber, but I have heard of others doing it.
titsonritz
09-27-15, 00:49
I know Glock absolutely recommendes against firing the 40 s&w in the 10mm chamber, but I have heard of others doing it.
They also recommend not using reloads, probably the same reason the in the article say "Don't do this", CYA.
So what kind of shooting are we doing?
I would thing that doing drills, and holster work would lead to a lot of malfunctions.
Unlike someone mentioned, I think most of the time the pickup rail (my word :)) would pick up the round and slide it under the extractor, I'd think you would have a lot of FTF because of the round working forward in the magazine and the steeper feed angles the shorter round would have as a result.
Does that seem plausible?
Pistol ammunition headspaces off the case mouth. Short brass can cause light primer hits.
I agree with Ryno. I would not make a habit out of it either.This 100%
Howdy MistWolf,
Stengun, you think the author is lying to us? You don't think he actually shoots 40 S&W through his 10mm Glock? You don't think I've got enough technical knowledge and experience under my belt to find the author's analysis plausible?
Just checking......
Like I posted earlier, I tried the .40 in my G20 and out of 10 rounds, it would only chamber and fire about 2 rounds before the round would miss the extractor and drop into the chamber without being fired when the striker would fire.
This is with a G20 that has fired +10,000 rounds without a hiccup of any type.
So, if the author is claiming that he and a friend have fired tens of thousands of .40S&W rounds through an unmodified Glock 20 10mm barrel, then, yes, I'm saying the author is lying.
And no, I'm not trying to insult your intelligence.
I truly wish the .40 in a 10mm trick would work back before there were $100.00 conversion barrels because .40 brass and loaded ammo is readily available.
Heck, yesterday I picked up 4.8 pounds of pistol brass at the range and there was a mix of 9mm ( 65% ), .45 ( 25% ) and .40S&W ( 10% ) and not a single freakin' piece of 10mm brass.
Finding 10mm brass at the range is like finding a smokin' hot 21yo virgin working in a strip club.
Paul
Howdy MistWolf,
Like I posted earlier, I tried the .40 in my G20 and out of 10 rounds, it would only chamber and fire about 2 rounds before the round would miss the extractor and drop into the chamber without being fired when the striker would fire.
This is with a G20 that has fired +10,000 rounds without a hiccup of any type.
So, if the author is claiming that he and a friend have fired tens of thousands of .40S&W rounds through an unmodified Glock 20 10mm barrel, then, yes, I'm saying the author is lying.
And no, I'm not trying to insult your intelligence.
I truly wish the .40 in a 10mm trick would work back before there were $100.00 conversion barrels because .40 brass and loaded ammo is readily available.
Heck, yesterday I picked up 4.8 pounds of pistol brass at the range and there was a mix of 9mm ( 65% ), .45 ( 25% ) and .40S&W ( 10% ) and not a single freakin' piece of 10mm brass.
Finding 10mm brass at the range is like finding a smokin' hot 21yo virgin working in a strip club.
Paul
Instead of assuming the author is lying, figure out why it works for him when it didn't work for you and whether his experience is the anomaly, or yours is. Then learning will take place
Howdy MistWolf,
Instead of assuming the author is lying, figure out why it works for him when it didn't work for you and whether his experience is the anomaly, or yours is. Then learning will take place
Like I posted earlier, BTDT and it just doesn't work.
Pretty simple.
Paul
Edited: I have a Lone Wolf 40-9mm conversion barrel for my G23. When I first bought this barrel back in '06 I posted a thread about it on GlockTalk and the vast majority of the responders claimed it woul never work because of the difference between the size of the rim on a .40S&W and that of a 9mm. After trying to explain that the was minimal difference that I finally gave up. +15,000 rounds later it still is 100%.
Howdy MistWolf,
Like I posted earlier, BTDT and it just doesn't work.
Pretty simple.
Paul
Edited: I have a Lone Wolf 40-9mm conversion barrel for my G23. When I first bought this barrel back in '06 I posted a thread about it on GlockTalk and the vast majority of the responders claimed it woul never work because of the difference between the size of the rim on a .40S&W and that of a 9mm. After trying to explain that the was minimal difference that I finally gave up. +15,000 rounds later it still is 100%.
Weird that it didn't work for you. I had no problems at all cycling .40s through my G20. I just don't think it's good idea.
If the writer of the article has ran 10s of thousands of .40 through his G20, more power to him. I feel it's a roll of the dice & it may eventually bite him.
Just because it hasn't worked with yours, doesn't mean it's not possible with anyone's. It only means yours won't cycle a caliber it wasn't designed for.
Howdy Ryno12,
Weird that it didn't work for you. I had no problems at all cycling .40s through my G20. I just don't think it's good idea.
If the writer of the article has ran 10s of thousands of .40 through his G20, more power to him. I feel it's a roll of the dice & it may eventually bite him.
Just because it hasn't worked with yours, doesn't mean it's not possible with anyone's. It only means yours won't cycle a caliber it wasn't designed for.
Cycling wasn't the issue. The issue is getting the extractor to reliability trap the cartridge as the slide locked up.
When the extractor missed the rim the round would drop into the chamber out of reach of the firing pin resulting in a misfire.
SAAMI specs list the .40 as being .142" shorter than a 10mm and a Glock 20's firing pin will not reach that far.
Heck, I've had light primer strikes that failed to fire the round in a .451 Detonics Mag barrel when I used .45ACP ammo and it's only .042" shorter than the .451.
I fully understand the "Just because it didn't work for me, doesn't mean it will not work for the next guy." line of thought.
Can it be done? Sure
Reliably enough to fire tens of thounds of rounds of ammo?
Not in a bazillion years.
Paul
Howdy Ryno12,
Cycling wasn't the issue. The issue is getting the extractor to reliability trap the cartridge as the slide locked up.
When the extractor missed the rim the round would drop into the chamber out of reach of the firing pin resulting in a misfire.
SAAMI specs list the .40 as being .142" shorter than a 10mm and a Glock 20's firing pin will not reach that far.
Heck, I've had light primer strikes that failed to fire the round in a .451 Detonics Mag barrel when I used .45ACP ammo and it's only .042" shorter than the .451.
I fully understand the "Just because it didn't work for me, doesn't mean it will not work for the next guy." line of thought.
Can it be done? Sure
Reliably enough to fire tens of thounds of rounds of ammo?
Not in a bazillion years.
Paul
Gotcha Paul, thanks for clarifying.
Singlestack Wonder
10-03-15, 22:51
Thus the term, "That Guy".........
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