I just was reading an old post on here from 2011. Seems there were a lot of folks ridiculing some members about their idea that firing a .40 cartridge from a 10mm Glock is dangerous. So anyway, I believe that it has been proven to be perfectly safe over the past several years, and there is enough evidence to sustain the claim without bashing folks for talking about it. Here is some bed time reading for you guys, and some videos as well with some more reading in the comments sections. http://www.thetruthaboutguns.com/2015/06/jeremy-s/40-in-a-10mm-glock/ https://www.youtube.com/watch?v=Vi7zJ6agymo https://www.youtube.com/watch?v=AwXtEm70Q0M
Firing .40 in a Glock 10mm.
- Thread starter robsguns
- Start date
Why? Possibly for the reasons given. Why not? I have no reason to doubt the information given in the link, but will note that firing a short cartridge in a gun made for a longer cartridge (like .45 GAP in a .45 ACP pistol) can always have problems not caused by lack of power (there is no significant difference in normal lads between 10mm and .40 S&W) but by such factors as the dimension of the magazine feed lips or the feed ramp. I wouldn't do it (except in an emergency) without a lot of testing with a particular gun.
I can see no reason for any danger in doing so.
Jim.
I can see no reason for any danger in doing so.
Jim.
Cheapshooter
New member
Why?
I bought a 10 MM because I wanted a 10 MM. If I want to shoot 40 S&W I'll shoot my 40 S&W
Maybe there's a demand for a Corvette with a Chevy Cruze engine.
I bought a 10 MM because I wanted a 10 MM. If I want to shoot 40 S&W I'll shoot my 40 S&W
Maybe there's a demand for a Corvette with a Chevy Cruze engine.
It will certainly work, and it's true that it's not extremely likely to ruin the gun or be unsafe. But it's also true that there is some potential for damage/danger.
Bullet material can be shaved/scraped off at the chamber mouth and may build up enough to create a partial obstruction.
Normally the case mouth is at the chamber mouth and there's no way for the lip at the chamber mouth to shave bullet material. When you fire a shorter round in an autopistol chamber the case mouth is back from the chamber mouth. That means the bullet is coming from far enough back that it can hit that lip and shave bullet material.
In a revolver chamber, the front of the chamber tapers so there's no possibility of shaving bullet material.
There's also some potential for headspace issues since extractors aren't generally specified to insure that they maintain proper headspace.
http://www.thegunzone.com/10v40.html
There are some other potential issues as well.
http://wethearmed.com/handguns/shoot-40-sw-in-a-10mm/
http://www.migunowners.org/forum/archive/index.php/t-184956.html
You can play the odds. A lot of people do and get away with it.
Another option is a conversion barrel. .40S&W conversion barrels for 10mm Glocks are available for as little as $100.
1. The chamber mouth of a revolver is tapered. No possibility of shaving bullet material.
2. Revolver cartridges headspace off the rim, not off the case mouth. A shorter cartridge in a revolver won't have headspace problems nor will it rely on the extractor to hold it in place.
Bullet material can be shaved/scraped off at the chamber mouth and may build up enough to create a partial obstruction.
Normally the case mouth is at the chamber mouth and there's no way for the lip at the chamber mouth to shave bullet material. When you fire a shorter round in an autopistol chamber the case mouth is back from the chamber mouth. That means the bullet is coming from far enough back that it can hit that lip and shave bullet material.
In a revolver chamber, the front of the chamber tapers so there's no possibility of shaving bullet material.
There's also some potential for headspace issues since extractors aren't generally specified to insure that they maintain proper headspace.
http://www.thegunzone.com/10v40.html
There are some other potential issues as well.
http://wethearmed.com/handguns/shoot-40-sw-in-a-10mm/
http://www.migunowners.org/forum/archive/index.php/t-184956.html
You can play the odds. A lot of people do and get away with it.
Another option is a conversion barrel. .40S&W conversion barrels for 10mm Glocks are available for as little as $100.
That's very different.
1. The chamber mouth of a revolver is tapered. No possibility of shaving bullet material.
2. Revolver cartridges headspace off the rim, not off the case mouth. A shorter cartridge in a revolver won't have headspace problems nor will it rely on the extractor to hold it in place.
I have a Glock 20 that in Oct 2014 I went out in the desert to shoot some really hot load 200 gr Nosler Power Pistol 1.28" work up with a KKM G20 40sw barrel and a 22 pound recoil spring assembly I built.
I would have been better off with my Bar-Sto 10mm barrel to shoot my 40sw work up.
I forgot to throat the chamber for the longer bullet seating.
I did not get far before I had a case failure.
Power Pistol knows when I jammed into the lands.
I would have been better off with my Bar-Sto 10mm barrel to shoot my 40sw work up.
I forgot to throat the chamber for the longer bullet seating.
I did not get far before I had a case failure.
Power Pistol knows when I jammed into the lands.
jetinteriorguy
New member
Um, someone please correct me if I'm wrong and I'll learn something new today. In a revolver the chamber is not tapered, the forcing cone is, which is part of the barrel not the chamber. The chamber is in the cylinder and is not tapered, at least not in my revolvers.
jetinteriorguy said:
Then either your revolvers are chambered for cartridges that headspace on the mouth (forward edge) of the case (45 ACP, 9mm, 10mm, etc) or, if your revolvers are chambered for rimmed cartridges (.38 Special, 357 Mag, etc), your chambers are not cut to SAAMI specs.
SAAMI spec for a .357 is here (bottom pic, top is cartridge):
http://www.saami.org/pubresources/cc_drawings/Pistol/357 Magnum.pdf
Note the taper that starts in the chamber (no sharp lip) 1.3019" from the breech face, which leads into the chamber throat.
A .38 Special chamber has the taper starting at 1.163" from the breechface, which cleverly prevents the longer, higher pressure .357 Mag cartridges from chambering:
http://www.saami.org/pubresources/cc_drawings/Pistol/38 Special_38 Special +P.pdf
SAAMI spec for a 10mm Auto is here:
http://www.saami.org/pubresources/cc_drawings/Pistol/10mm Automatic.pdf
Note the sharp lip located at 0.992" from the breech face. A 10mm cartridge headspaces on that lip. A 40 S&W will be held against the breech face by the extractor (hopefully) a given distance from the sharp lip (about .992" - .850" = .142") and, as JohnKSA stated, that sharp lip is just waiting to shave your bullets and build up a nice ring in the chamber for you.
A 40 S&W chamber has the sharp lip for the cartridge to headspace against at 0.850" from the breechface:
http://www.saami.org/pubresources/cc_drawings/Pistol/40 SandW.pdf
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I have done enough research on this subject, through the use of the internet, to know that there are a lot more shooters than I can count firing .40 (hundreds of rounds in most cases, thousands in others) out of their 10mm Glocks with no ill effects. Does that mean it is safe to do so, with no chance of ill effects? No, it doesn't, but no more so than firing 10mm out of a 10mm Glock, in my book anyway. I've seen more case ruptures and blown barrel chambers on a Glock 10mm from shooting 10mm through a Glock barrel than I can count. I have not seen anyone post pictures of this type of failure from firing .40 through a Glock 10mm barrel. If I were making a habit of doing this, and I broke an extractor, for what they cost, it would not bother me one bit, after saving the amount of money I would have, firing .40 over 10mm. Will I regularly fire .40 through my 10mm Glock barrel? No, because I have handguns chambered in .40 for that, Glocks included, so I have no need to buy a conversion barrel for my 10mm Glock, or fire .40 through my 10mm Glock. However, it is nice to know that if I am in a jam, in my book anyway, it is just as safe to use the .40 as what I would expect it to be firing the 10mm. I knew this would be a topic that would generate conversation, but I wanted to bring it up again, in light of the previous thread on it from 5 years ago getting almost nothing but negative comments, and see if the passing of time would show a more favorable outlook on this practice today. I believe the comments do show that it is generally more accepted to be a practice that can be done, mostly in a situation dictating it as a matter of 'no choice', but at least it is being recognized as an alternative to being out of ammo when the 10mm ammo has been expended and the .40 ammo is still in the closet or truck and you are holding a 10mm in your hand. Thank you for all of the feedback, positive and negative.
All of the people I know personally who shoot 10mm reload for it at a significantly lower cost per round than the cost of any factory .40S&W. Arguably superior ballistics at a lower cost. A S&W 610 revolver will definitely shoot either caliber if a 10mm handloader wants to shoot some .40S&W out of the same gun.
SGAmmo.com - Sellier and Bellot 10MM. Last week. $14.95 a box - I ordered 6 boxes and shipping was $12. I think its $1 off per box if you order in quantity. The ammo has come in and out of stock at least twice in the last month so it seems they have a supply of it somewhere.
stagpanther
New member
Agree with JohnK--I'm no expert but I own and have shot a glock 20 for a long time. My experience with cartridges with varying headspace in the glock is that mostly you'll be OK--but in general not a good idea IMHO. given the different case length dimensions there is inherent unpredictability IMO as to how well the case will seal to the chamber--not to mention primer strike reliability.
From the op:
It can be done. Main question is why you would do it other than in an emergency.
I can bake a gun in a casserole, or into a batch of mac and cheese...but why?
I can also shoot 380 acp from a 9mm. 9mm from a 38 Super, 357 Sig from a 40 S&W, but why?
Because it can be done sometimes, does not make it a good practice. Should we advocate that if a fella wants a gun in 40 S&W they forgo that for the "2 round" gun? That all 10mms are now "40S&W/10mm" guns in the way that 38/357's are?
I also have to question the assumption that..."So anyway, I believe that it has been proven to be perfectly safe over the past several years"
It's that word "safe" that gets in the way. It assumes that 5,000 or more rounds of 40 S&W have been fired through a good many Glock 20s without incident of any type related to the round being shorter in overall length than the 10mm.
Shooting some rounds of 40 S&W from a 10mm gun does not make it a useful practice to encourage across the board or to declare that it's a good practice and a safe one, or as good as having a gun in 40 S&W.
Does this hold true for other guns or just Glocks? Should we encourage the same experiments from a S&W 1006 or a 1911 in 10mm?
Is it as reliable as 38 Spl. from a .357 mag, the 44 Spl. and the 44 Mag (guns which were specifically built for 2 rounds)?
Can we promote all 10mms as "safe" for 40 S&W?
If we can't then what's the point?
If the point is that oyu can do it sometime in a pinch...then OK.
There are benefits to shooting a gun in the caliber it was built for. It generally means reliability is enhanced. As the proper magazine enhances reliability. In the case of the 40 S&W the gun is smaller and lighter.
Those are my hesitations about recommending it as good practice.
tipoc
It can be done. Main question is why you would do it other than in an emergency.
I can bake a gun in a casserole, or into a batch of mac and cheese...but why?
I can also shoot 380 acp from a 9mm. 9mm from a 38 Super, 357 Sig from a 40 S&W, but why?
Because it can be done sometimes, does not make it a good practice. Should we advocate that if a fella wants a gun in 40 S&W they forgo that for the "2 round" gun? That all 10mms are now "40S&W/10mm" guns in the way that 38/357's are?
I also have to question the assumption that..."So anyway, I believe that it has been proven to be perfectly safe over the past several years"
It's that word "safe" that gets in the way. It assumes that 5,000 or more rounds of 40 S&W have been fired through a good many Glock 20s without incident of any type related to the round being shorter in overall length than the 10mm.
Shooting some rounds of 40 S&W from a 10mm gun does not make it a useful practice to encourage across the board or to declare that it's a good practice and a safe one, or as good as having a gun in 40 S&W.
Does this hold true for other guns or just Glocks? Should we encourage the same experiments from a S&W 1006 or a 1911 in 10mm?
Is it as reliable as 38 Spl. from a .357 mag, the 44 Spl. and the 44 Mag (guns which were specifically built for 2 rounds)?
Can we promote all 10mms as "safe" for 40 S&W?
If we can't then what's the point?
If the point is that oyu can do it sometime in a pinch...then OK.
There are benefits to shooting a gun in the caliber it was built for. It generally means reliability is enhanced. As the proper magazine enhances reliability. In the case of the 40 S&W the gun is smaller and lighter.
Those are my hesitations about recommending it as good practice.
tipoc