Why 10mm in a revolver?

Recycled bullet said:
Maybe it's for somebody likes to shoot 10 mm and yet at the same time hates to chase brass.

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Definitely one of my thoughts. Along this line I’ve always thought a nice six shot revolver in 9mm with a 3” barrel and a shortened frame/cylinder would be handy. Easier to conceal with good performance. I suppose the same criteria applied to a 10mm would be handy.
 
Pumpkin said:
Sign me up for a 6 shot 9mm too!
Something very similar to the 547 S&W.;)
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Yup, except for a shorter frame/cylinder to take advantage of the shorter case for better concealment and a 3” barrel. I’d definitely be in on that. I’d probably even be in on a five shot in 10 mm with the same characteristics, but I’m covered by my two Model 57’s in a larger caliber. Another nice feature is the ability to still extract cases fully even with a shorter extractor.
 
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Originally posted by reddog81
That's great but I just looked at SGAmmo website to compare prices against 10mm and it was cheaper than all the others by a bit and 40 S&W is cheaper by a noticeable margin.
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That's funny because I just looked at SG ammo and they have this nifty little feature where you can sort listings by Price per round. The lowest price 10mm is 1000 round cases of either S&B or Magtech 180 gr FMJ which are both $.40/round. The cheapest .38 Special is a 1000 round case of Magtech 158 gr LSWC which is $.40/round. The cheapest .45 ACP is 1000 round cases of either S&B or Magtech 230 gr FMJ that are, again, $.40/round. Only .357 Magnum is more expensive than 10mm but any .357 Magnum revolver can shoot .38 Special as a sub load.

While .40 S&W ammunition can be used in some 10mm revolvers, this isn't universally true. While not particularly common, there have been 10mm single-action revolvers made and, because they load and unload through a loading gate, such guns cannot use moon clips and therefore cannot use .40 S&W ammunition. Also, Ruger specifically states in the owners manuals for both the GP100 and Super Redhawk that they "will function, and has been tested, with 40 S&W caliber ammunition, but may misfire (fail to fire) with some commerical ammunition. For this reason, Ruger does not recommend the use of 40 S&W ammunition in this revolver." I suspect that this is because there's enough flex in the moon clip to allow certain ammunition with harder primers to fail to fire. The versatility of using .40 S&W seems greatly diminished if you have to cherry pick certain brands of ammunition that will be reliable, or can't use it at all.

People aren't buying 50 different offerings of 38 Special and half of those listed probably haven't been made for years/decades anyways.
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No, people aren't buying 50 different offerings, but if 50 different offerings are available, you're more likely to be able to find one offering you need/want. By and large, 10mm comes in two flavors: FMJ and JHP though a few of the boutique makers offer hardcast flatnose and specialty bullets like the Lehigh Xtreme Penetrators/Defenders or frangibles. I can get .38 Special in FMJ, JHP, LSWC, HBWC, HC-WC, LSWCHP, LRN and all of the specialty bullets. Also, I don't know where you're getting this idea about the .38 Special ammunition listed not being made for years/decades. All of the loadings I referenced in my previous post are currently cataloged by the manufacturers I mentioned and most of them I could go and buy today.

I don't know what % of people buy ammo in gun shops anymore but I know 95%+ the factory ammo i've bought in the last decade has been from online vendors.
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Buying ammo online really only makes sense if you're buying in large quantities or looking for something that's difficult to find in a brick-and-mortar store. If you're just buying one or two boxes of commonly-available ammunition, the savings from buying online are quickly eaten up by shipping costs. A lot of people don't buy ammo in bulk but rather just buy a box or two when they want to go to the range, those people I think are much more likely to simply go to a brick-and-mortar store than buy online, pay the shipping costs, and wait for their ammo to be delivered.
 
Webleymkv said:
While not particularly common, there have been 10mm single-action revolvers made and, because they load and unload through a loading gate, such guns cannot use moon clips and therefore cannot use .40 S&W ammunition.
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Why is the loading gate on a single action a problem for .40 rounds?

You would not need a moon clip, just put them in and punch them out like all cartridges.

Right?
 
The Verminator said:
Why is the loading gate on a single action a problem for .40 rounds?



You would not need a moon clip, just put them in and punch them out like all cartridges.



Right?
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I suppose it would work like that if the cylinder was cut for the depth of 40 Smith & Wesson. Is there an alternative way to control case head position on a rimless cartridge in a gun that does not have an extractor claw?

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Originally posted by The Verminator
Why is the loading gate on a single action a problem for .40 rounds?

You would not need a moon clip, just put them in and punch them out like all cartridges.

Right?
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Typical "revolver" cartridges like .38 Spl, .357 Mag, .44 Mag, .45 LC, etc. utilize their rim not only for extraction (at least in a top-break or swing-out cylinder) but also for headspacing. This is why it's perfectly safe to shoot shorter cartridges like .38 Special or .44 Special in guns chambered for longer ones like .357 Magnum or .44 Magnum: they all headspace on the rim.

Because 10mm and most other "semi-auto" cartridges are "rimless" in that their rim is the same diameter as the case body, they need to headspace on the case mouth instead. Because the .40 S&W is shorter than 10mm, if simply slipped into the chamber unsupported it will go too deeply into the chamber before it's case mouth abuts against the "step" milled into the chamber for headspacing. This is why, though some people do it anyway, shooting .40 S&W through a 10mm semi-auto isn't a recommended practice as you're relying solely on the tension of the extractor for headspacing, something the extractor was not designed to do. With a revolver that uses moon clips, you can usually get away with shooting .40 S&W because the moon clip supports the cartridge enough to act the same as the rim on a "revolver" cartridge would. However, with a gate-loading revolver, there is no moon clip or extractor to hold the cartridge back against the recoil shield and thus the .40 S&W cannot headspace properly in a 10mm chamber.
 
“While .40 S&W ammunition can be used in some 10mm revolvers, this isn't universally true. While not particularly common, there have been 10mm single-action revolvers made and, because they load and unload through a loading gate, such guns cannot use moon clips and therefore cannot use .40 S&W ammunition. Also, Ruger specifically states in the owners manuals for both the GP100 and Super Redhawk that they "will function, and has been tested, with 40 S&W caliber ammunition, but may misfire (fail to fire) with some commerical ammunition. For this reason, Ruger does not recommend the use of 40 S&W ammunition in this revolver." I suspect that this is because there's enough flex in the moon clip to allow certain ammunition with harder primers to fail to fire. The versatility of using .40 S&W seems greatly diminished if you have to cherry pick certain brands of ammunition that will be reliable, or can't use it at all.”

Could this have something to do with the difference in primer size between 10 and 40?
 
Originally posted by Pumpkin
Could this have something to do with the difference in primer size between 10 and 40?
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I don't really see how it could as the same or similar models are made in .357 Magnum which uses a small pistol primer like .40 S&W and I've even come across some 10mm brass with small pistol primers.

My best guess is that the moon clips have a little bit of flex to them and, if you're shooting .40 S&W which doesn't have it's case mouth supported by the chamber like 10mm would, the cartridge can move forward just enough when struck by the firing pin that the primer isn't ignited. This probably isn't a common problem with other moon clip revolvers because either there is no commonly available shorter cartridge to be used as a sub load, as would be the case with 9mm and .45 ACP, or they're using traditional rimmed cartridges like .38 Special or .357 Magnum which rely on their rims abutting against the outer edge of the cylinder for headspacing anyway.
 
Webleymkv said:
Typical "revolver" cartridges like .38 Spl, .357 Mag, .44 Mag, .45 LC, etc. utilize their rim not only for extraction (at least in a top-break or swing-out cylinder) but also for headspacing. This is why it's perfectly safe to shoot shorter cartridges like .38 Special or .44 Special in guns chambered for longer ones like .357 Magnum or .44 Magnum: they all headspace on the rim.

Because 10mm and most other "semi-auto" cartridges are "rimless" in that their rim is the same diameter as the case body, they need to headspace on the case mouth instead. Because the .40 S&W is shorter than 10mm, if simply slipped into the chamber unsupported it will go too deeply into the chamber before it's case mouth abuts against the "step" milled into the chamber for headspacing. This is why, though some people do it anyway, shooting .40 S&W through a 10mm semi-auto isn't a recommended practice as you're relying solely on the tension of the extractor for headspacing, something the extractor was not designed to do. With a revolver that uses moon clips, you can usually get away with shooting .40 S&W because the moon clip supports the cartridge enough to act the same as the rim on a "revolver" cartridge would. However, with a gate-loading revolver, there is no moon clip or extractor to hold the cartridge back against the recoil shield and thus the .40 S&W cannot headspace properly in a 10mm chamber.
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Ok, that makes sense.

Thanks for the help.

I can see how the .40 would then slide in too far in the single action.
 
primer size is not the issue, the issue is "keeping the cartridge from sliding too far into the chamber" aka "head space”

I know the head space is wrong but what about all the Colt 1917 45 ACP revolvers.
I thought they would only function properly with 45 ACP and half moon clips?
Or 45 Auto Rim.

Are the 10mm moon clips appreciably thinner than the 45?
 
OK, you're right, 10mm is a terrible option because the cheapest options are all priced the same...

I checked the 3 different vendors I buy from and they had 6, 7, and 8 of the 17 different Winchester 38 special options you mention as available.

Everyone I know who shoots a lot buys online. The days of showing up at the range or on the way to the range and expecting to buy ammo are kind of over unless you get lucky or are willing to pay through nose either way.

Good grief. Like I said before - it's not that 10mm is the best option, but it is pretty much on par with the other common calibers and depending on your situation it might be a logical choice.
 
It's not something I'd be interested in. A 10mm pistol is the equivalent of a comparably sized 357 mag. A 4.5" Glock 20 is about the same overall length as a 3" K or L frame 357 mag.

Power levels are about the same with similar bullet weights. I can shoot 155's in my 10mm and do about anything I can do with 158's from a 357 mag revolver. Ditto that with 180 or 200 gr bullets. There are 220 gr 10mm loads, but I'm not sure they are a better option than the 200 gr loads.

There are some guys who simply prefer revolvers but personally I'd stick with a 357 mag revolver instead of a 10mm revolver. But everyone is different and that's why they make them.
 
I'd be willing to bet that "flex" in a moon clip allowing for less than reliable ignition (as in .40S&W in a 10mm chamber) would only be an issue using plastic/polymer clips.

Traditionally, from the earliest days of half moon clips in the 1917 .45ACP revolvers, the clips were steel. Thin, yes, but steel. Steel that doesn't flex like plastic/polymers can.

Downside of steel is, of course, rust, and the fact that once bent, they stay bent until straightened. Plastics /polymers don't rust and have a degree of flex and return to true steel doesn't have.

SA revolvers firing rimless rounds get away with it by using a separate cylinder for them. The SA's allow the case to headspace on the case mouth, and the poke them out one at a time ejection doesn't care about rimmed or rimless.
 
Originally posted by 44 AMP
I'd be willing to bet that "flex" in a moon clip allowing for less than reliable ignition (as in .40S&W in a 10mm chamber) would only be an issue using plastic/polymer clips.

Traditionally, from the earliest days of half moon clips in the 1917 .45ACP revolvers, the clips were steel. Thin, yes, but steel. Steel that doesn't flex like plastic/polymers can.

Downside of steel is, of course, rust, and the fact that once bent, they stay bent until straightened. Plastics /polymers don't rust and have a degree of flex and return to true steel doesn't have.
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I wouldn't have thought it would be an issue with steel moon clips either, but apparently it's enough of an issue for Ruger to mention it in their owner's manual and I can't think of any other reason why you would get misfires with .40 S&W in moon clips.

I seem to recall that while the S&W 1917 revolvers always had the "step" machined into the chambers, some of the early Colt 1917's had their cylinders bored straight through thus making moon clips mandatory for both headspacing and extraction, thus making the issue with shooting .40's in a Ruger revolver all the more curious.

The only explanation I can come up with is that every picture of 10mm moon clips I've seen has a groove cut in between where the cartridges go while .45 ACP moon clips generally lack this groove. You can see what I'm referring to in the pictures on Ruger's website.

https://shopruger.com/Super-Redhawk-10mm-Auto-6-Round-Moon-Clips-3-Pack/productinfo/90515/

Perhaps this groove allows more flex in the moon clip than more traditional ones which lack this feature? Like I said it's a curious situation especially since they don't mention similar issues with the Redhawk that can fire both .45 Long Colt and, with moon clips, .45 ACP which also appears to use "grooved" moon clips. Perhaps, because the cylinder is machined differently to allow .45 LC to be used without clips, the case is better supported and thus prevents the issue? I really don't know, as I said it's a very curious situation.
 
I wouldn't have thought it would be an issue with steel moon clips either, but apparently it's enough of an issue for Ruger to mention it in their owner's manual and I can't think of any other reason why you would get misfires with .40 S&W in moon clips.
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The quote from the Ruger manuals says "has been tested and works", so, I'm thinking that with Ruger clips, (steel) there likely won't be an issue. However, the quote also says they don't recommend using .40 S&W because some ammo might not work well. TO me, that says Ruger CYA as they will not endorse ammo they haven't tested, and proved reliable. Also, Ruger has no way of knowing if you are using their clips or not.

I seem to recall that while the S&W 1917 revolvers always had the "step" machined into the chambers, some of the early Colt 1917's had their cylinders bored straight through thus making moon clips mandatory for both headspacing and extraction, thus making the issue with shooting .40's in a Ruger revolver all the more curious.
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The very first batch of Colt 1917 revolvers had cylinders bored straight through, and so lacked the headspacing ledge that S&W put in their guns. So, the first Colts needed clips in order to work at all. S&W guns only needed clips for simultaneous ejection.

Every batch of Colt 1917s after the first one had the headspace ledge in the cylinder like the S&Ws did. After WWI, those first batch Colts were reworked and the cylinders were replaced with ones which had the headspace ledge.

IF you can find a Colt 1917 that still has a bored straight through cylinder, it is a real rarity, as it is a gun that somehow escaped the rebuild process.

The .45AR came out in the 1920s, from Peters, originally, so civilian owners could use 1917 revolvers without needing clips.

Not every (more modern) .45 acp revolvers can use .45 Auto Rim cases. Some can, some cannot.
 
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