Using 40 brass for 10mm loads

[devster55]

Ok first off I am not going to do it as my gun and face are worth more than saving a few bucks. So secondly I heard someone say that they used 40 brass to load plinking ammo for the 10mm. Just curious what load and col did you use.

[ptmn]

Not a good idea, smaller case capacity will cause way higher pressures if you use 10mm data. If the extractor doesn't hold the 40 case against the breach, you could have major headspace problems too.

[devster55]

See that's what I thought as well. I thought the auto loaders headspace off of the mouth of the case so I do not understand how someone could do it. I changed my first post to say will not instead if think I won't as I was just curious and am not going to do it.

[drdarrin@sbcglobal.net]

A 40 S&W can be fired in a 10mm, if the extracter holds it against the breech face so the firing pin can strike the primer. I have several examples (not mine) where 9mm's were fired in a 40. Surprisingly, they didn't split.

This is the same concept as firing 44 Spl in a 44 Rem Mag or a 38 in a 357; except that they headspace off the rim not the case mouth like the 10/40.

Personally, I wouldn't recommend this practice but it's you gun OP. I doubt it would be dangerous as long as you don't load 40's to mimic 10mm performance. I doubt your pistol will cycle properly. But I could be wrong.

I'll hold your beer.

[devster55]

Just to be clear I am not going to do this. Someone said that they do it in one of my other threads. I am just curious say if 10mm brass was extremely scarce.

[ihasacookie]

I've also read such a thing on another forum. They seat the bullet shallow to match 10mm COAL and load to minimum specs from what I recall. But then again I've also read that pigs fly on Reddit...

[sargenv]

It works best in the 40 S&W 610 Revolver since the cartridges actually headspace on the moon clip and not the mouth of the case.. In this case it really is like firing 38 spl in a 357 mag chamber.. Otherwise I would suggest you get a 40 S&W barrel for your 10 mm handgun, change out the springs and the magazines should work fine.. though you might have to seat the bullet longer for them to feed from the magazines..

[Dark Mod]

Whats funny is that .40 can easily be loaded to commercial 10mm pressures and beyond. Most of the commercial 10mm ive used has been laughably underpowered, some were right around the same manufacturers offering in .40.

Now if you want to load a warm 10mm load in a .40 case (Say a 180 grn bullet at 1200 fps) no way, i wouldnt even play around with it. Keeping that same projectile around 1000 to 1050 should be fine, and right on par with a lot of the 10mm rounds you would take out of a box.

To your original point, ive found evidence of people loading .40 at charges exceeding 10mm max load for the same bullet/powder:

http://handloads.com/loaddata/?Caliber=40+SqqqW&Weight=All&type=Handgun

I probably should say i in no way encourage exceeding max published data for any cartridge

[Carcassonne]

Just to be clear I am not going to do this. Someone said that they do it in one of my other threads. I am just curious say if 10mm brass was extremely scarce.

It is available new, but once fired brass isn't easy to find or cheap.



.

[J-cat]

A couple of issues:

Head spacing off the extractor creates an ignition reliability issue. There is too much gap and the case slides forward under impact from the firing pin, lessening it's effect. This can be compensated for with the use of soft cup primers such as FC-100. They are less sensitive to light strikes than WSP or CCI primers.

Second, the bullet free floating from the case into the freebore is unlikely to enter dead on and will scrape against the sharp shoulder whose function is to head space the case. The bullet will scrape and the scrapings will build up. Subsequent chambering of 10mm ammo will be problematic. This can be compensated for by loading 180/200gr bullets to 10mm OAL as they will sit well aligned in the freebore when the round chambers.

In an emergency, don't hesitate. It's better than a sharp stick.

[robert101]

See Post #6. That is what I have heard as well. They apparently try to get the OAL of the 40 S&W very close to the 10MM chamber. In effect the elongated cartridge how headspaces on the "lands" and fills the chamber. This in their theory would help mitigate the extractor alignment issue. Also, keep in mind that loading a cartridge to the lands can in itself create a higher pressure. So as mentioned previously those who choose to try this might want to keep the pressures on the mid to low side. Just for the fun of it, I might try to see what the OAL of a dummy round 40 S&W to 10MM has to be in order for it to work in my DW 10MM.

[J-cat]

It does not headspace off the lands. It is nowhere near the lands for headspacing purposes.

[stilly]

Not a good idea, smaller case capacity will cause way higher pressures if you use 10mm data. If the extractor doesn't hold the 40 case against the breach, you could have major headspace problems too.

THAT is the key here.

SO, you had BEST pull your pills out a bit and make the entire round a bit longer so that the pill is resting on the barrel rifling. I forgot, the lands or whatever. It is doable. I know of a someone here that does it.

But to just jam a 40 cal into a 10mm then you COULD have the same scenario as above, which means it might fail to fire...

Just to be clear I am not going to do this. Someone said that they do it in one of my other threads. I am just curious say if 10mm brass was extremely scarce.

You chicken?

Bro, this is the interwebz. You do not need to announce to US that you aint gonna do it. Hell, give me your gun, I will do it for you... But here is the deal, 10mm brass is kinda rare, but not really. You can find it but you just gotta look for it. Lotsa folks have it online. I have over 500 shells now + the blasting ammo I got from Freedom Munitions.

When I get to loading my 10mm up I am gonna load some longshot 10mm cause I heard it was da BOMB...

[devster55]

^^^^ yeah I was searching high and low for some longshot locally. I ended up with some power pistol cause that's all I could find.