40 in 10mm reloads

[WestKentucky]

I have seen multiple reports of people shooting 40sw in 10mm guns regularly, and I have recently seen a pretty convincing argument as to why that might be an acceptable practice provided that the individual understand what they are doing and make a decision on whether they think it wise or not. That said... with so many folks shooting 40 in 10mm guns, is there a way to reload .40 cases in such manner to intentionally use them in 10mm guns by loading longer and using a slightly heavier crimp to make up for reduced neck tension.

 

[gotboostvr]

I'd try them as-is, if they work I wouldn't bother fiddling with it.

If they didn't work conversion barrels or a simple spring change usually are available for a reasonable price.

 

[WestKentucky]

I'd try them as-is, if they work I wouldn't bother fiddling with it.

If they didn't work conversion barrels or a simple spring change usually are available for a reasonable price.

Agreed, it’s not advisable and it would be easy to either get a conversion barrel or get a bag of proper brass, but with the plethora of shooters shooting 40 in 10, surely someone has done something to make it closer to the actual 10mm when they load.

 

[<*(((><]

Make sure your extractor is grabbing at full tension as that is what would be holding the 40 against the breechface.

The same argument could be made shooting 380acp in a 9mm

Never done either, but don't see why it wouldn't work. Would I do it, probably not, especially with how cheap .40 cal pistols are these days. One practically trips over them walking into a pawn shop these days.

 

[FROGO207]

With the 40 one is looking for economy. With the 380 in 9MM that is not the.case though. I would not depend on a 40 working in a 10MM but for target practice you might get it to work out of OK.

 

[Herman B]

I have no experience shooting 40 in a 10mm firearm but know that many people do exactly that with their Glocks. I would abide by standard 40 SAAMI specs and 40 load data when doing so. No reason to play with pressures. There isn't any point in a 'heavier' taper crimp as it may deform the bullet while not providing additional tension due to brass springing back...unless you go way overboard and mash the mouth and deform bullet, potentially increasing pressure. Taper crimp isn't so much a crimp to create neck tension as it is merely straightening the bell.

 

[<*(((><]

I would imagine an unintended consequence of saving money shooting .40 in 10mm would be premature extractor wear.

 

[mdi]

Does the semi-auto 10mm headspace on the case mouth like a 45 ACP? Many, many times I have fired 38 Spec in 357 Mag. guns and 44 Special in 44 Mag guns but they headspace on the rim, wouldn't there be a problem just relying on an extractor to hold a round in place?

BTW; a 9mm cartridge is .381" OD whereas a 380 ACP cartridge is .373" OD. I wouldn't shoot a 380 in a 9mm gun...

 

[jmr40]

I've tried it enough in my Glock 20 and 29 to convince myself that it works, accuracy and POI are the same. I don't plan to make a habit of it though. I don't bother handloading for 10mm and at one time 10mm ammo was harder to find and more expensive. My local gunshop carries a good supply of 10mm ammo now priced exactly the same as 40 S&W so there is no incentive. But if in an emergency and 40 is all I can get my hands on, and the 10mm is the pistol in my hand it is good to know it will work.

 

[crestoncowboy]

I'm one of the ones who has done it a lot. In many guns. That said, if I'm reloading I just reload 10mm. It costs the same to reload 10 as 40. Even uses the same dies. I don't see why anyone would bother? The whole in shooting 40 in a 10 is getting cheap bulk ammo. Or at least that is why I always did it.

 

[crestoncowboy]

My local gunshop carries a good supply of 10mm ammo now priced exactly the same as 40 S&W so there is no incentive.

I just recieved 1k ranger t in 40 for 208.00. (LAX ammo. First time I used them actually) There are some great deals on 40.

 

[Herman B]

Does the semi-auto 10mm headspace on the case mouth like a 45 ACP? ...wouldn't there be a problem just relying on an extractor to hold a round in place?

Yep, the 10mm cartridge headspaces on the case mouth. I've not heard of problems with 40 headspacing on the Glock extractor...people have shot thousands of such rounds without incident but it's not for me.

My guess is that people shoot 40 in their 10 guns largely because of the abundance of cheaper/free brass.

 

[cfullgraf]

With mood clips, you can shoot 40 S&W in a 10mm revolver.

Many moons ago, I tried shooting 9x19 in a 9mm Largo semi-auto and it kind of worked but after trying it I would not recommend it.

Ditto with shooting 40 S&W in a 10mm chambered semi-auto unless I had a 40 S&W chambered barrel.

 

[1-12 INF (M)]

It does work, but rimless cartridges headspace on the case mouth - not like rimmed ones at all. You're depending on the extractor to hold the cartridge in the chamber. If you want .40 level performance in a 10mm, the proper thing to do is download a 10mm case to the velocity you want.

 

[Paul Toms]

No. No. No. Just, no.

 

[larryh1108]

As has been mentioned, shooting .40 in a 10mm barrel requires the extractor holding the round against the breech face. Will it work? Sure. Will it, one day, affect your extractor? Probably. However, since it's a Glock it will never break.
Do it in a 1911 and a new extractor is on the horizon. Also, I wonder if you get the same carbon ring you get in revolvers when shooting .38Special/.357 or .44Special/.44Mag?

 

[Rule3]

Gee is the barrel marked 40 SW AND 10MM either/or your choice?
If you want the 40 SW than shoot a 40SW gun Why have it hanging on the 10mm extractor?

 

[dredd]

As with many things in life...

Just because you can, doesn't mean you should.

But seriously.... Do what makes you happy and keeps you safe.

I like shooting 10MM in my G20 & G29 so I won't be surprised by them feeling "different" when I actually need to put them to use.

 

[ATLDave]

Beware! There are some guns where this is sorta safe, and some guns where it is not safe. See, e.g., this thread: https://forums.brianenos.com/topic/280770-shoot-40-out-of-a-10mm/

 

[1-12 INF (M)]

This reminds me of the old days when the Astra 400 (9mm Largo) could shoot 'any 9mm cartridge'. Well, no. It' can't.

 

[1-12 INF (M)]

There's no reason to do this. We're not talking about a TEOTWAWKI scenario. I compared prices just now on Midway USA - S&B 10mm for $16.99 and Win .40 S&W for 15.99. It's like watching a guy with a $2000 military rifle with a $3000 optic shoot steel cased Combloc ammo and wonder why the performance sucks. Really people, look at the pistol and match up the caliber rollmarked on it with what's printed on the box. If you can't afford the gun, then you can't afford the ammo.

 

[mdi]

Many different opinions from "sure, I do it all the time" to "no, no, no, no". IMO, this is where reloading comes to play and if I wanted 40 level ammo, I'd reload my 10mm brass to 40 levels.. I don't have a 40 S&W or 10mm, but I have 5 revolvers that can shoot Specials and Magnums interchangeably. But since I don't load to "save money" ,, I tailor my loads all the way from mild to wild in the brass designed for the gun. I didn't start out with that in mind but it has worked out this way after 30+ years. As for a SHTF scenario, I have reloaded and stashed a few thousand rounds (for 4 guns) that I call my "Just In Case Ammo". So, for me, buying in bulk to save money only applies to components...

 

[crestoncowboy]

Every one I have also says not to use ammo that's reloaded or remanufactured, many even throw in that it must be recently manufactured. And to thoroughly read the owners manual........i once fired a 223 round through an AR. I even shot lead from Glock and HK.....I guess I'm just a rebel

Not saying anything I do should be tried at home. But research everything for yourself.

But I do agree. Not a good thing to ignore the markings. use the correct ammo.
But remember years ago 10mm was not cheap and not easy to find either. That's when this debate made sense

 

[crestoncowboy]

I didn't start out with that in mind but it has worked out this way after 30+ years.

That's what I'm screaming. I get the feeling that most of the guys werent trying to buy 10mm before the internet and after all the Norma dried up. Winchester Silvertips and hornady custom were about the cheapest. 18-20 bucks for 20.

Does it make sense now to do it??. No probably not.