My .40 will chamber a .357 sig

[TurboChrisB]

So I already had a SigPro 2340 in .40....today I picked up another Sig 2340 in .357..since the mags are interchangeable I was curious as to what happens if you put a mag with .357 into the .40 and vice versa...well, I can rack it and chamber a .357 into the .40 but not the .40 into the .357...

So now I'm curious what would happen if someone chambered a .40 with a .357 round and pulled the trigger? Would nothing happen or would I get the big bang with ugly results? Anyone know? Surely someone must have done this accidentally before...

[toby]

You really should'nt have to ask?,,,,,

[RobG]

Seriously? This has to be a trick question

[Sinixstar]

Let's think about this real hard.

Gun is chambered for .40 S&W, you drop a .357sig in there.

.357sig =/= .40S&W

is there really any more that needs to be said?

[kel-tec-innovations]

This happened with my Glock .40 and .357 and they use the same magazine and I accidental put a .40 into my .357 glock and I pulled the trigger but luckily the slide doesn't close all the way and the bullet didn't go off other wise it would be bad. I would imagine barrel damage if it goes off.

[cgseanp1]

I must be an idiot cuz I don't know what would happen. Maybe one of those 3 guys that posted above could enlighten us since it's sooo obvious

[railroader]

So I already had a SigPro 2340 in .40....today I picked up another Sig 2340 in .357..since the mags are interchangeable I was curious as to what happens if you put a mag with .357 into the .40 and vice versa...well, I can rack it and chamber a .357 into the .40 but not the .40 into the .357...

So now I'm curious what would happen if someone chambered a .40 with a .357 round and pulled the trigger? Would nothing happen or would I get the big bang with ugly results? Anyone know? Surely someone must have done this accidentally before...

Being the bottom half of your brass is 40 cal you would probably get away with. The neck might get resized up to 40 cal and the 9mm bullet would go rattling down the barrel. Mark

[Sinixstar]

I must be an idiot cuz I don't know what would happen. Maybe one of those 3 guys that posted above could enlighten us since it's sooo obvious

The extent and severity could range anywhere from simple malfunction all the way to deadly catastrophic failure.

Does that make it clear enough?

yes, it should be painfully painfully obvious that you should only shoot ammo that your gun is chambered for. This is up there with "don't point a loaded gun at your own face and pull the trigger" in terms of proper gun handling as far as i'm concerned.

If you really have to ask about shooting the wrong caliber of ammo out of your gun - you very well may want to consider a hobby in stamp collecting instead of guns.

[masameet]

Don't you need a different guide rod and barrel if using the same frame?

I was offered in trade a SIG P229 in .40 with a .357 barrel and guide rod but passed on it.

And late last year I let somebody shoot my .45. She was having a blast until she got a FTE. She handed my 1911 to me to clear it and darned if a spent casing wasn't stuck in the barrel. Turned out in reloading the empty mags, she'd slipped some .40 rounds in with the .45 rounds. The .40 round fired but the casing stuck. At that point I should have made her empty out all the mags she had loaded. Oh well. Live and learn.

[toby]

I think there are some people that should not have firearms!..

[RobG]

The extent and severity could range anywhere from simple malfunction all the way to deadly catastrophic failure.

Does that make it clear enough?
yes, it should be painfully painfully obvious that you should only shoot ammo that your gun is chambered for. This is up there with "don't point a loaded gun at your own face and pull the trigger" in terms of proper gun handling as far as i'm concerned.

If you really have to ask about shooting the wrong caliber of ammo out of your gun - you very well may want to consider a hobby in stamp collecting instead of guns.

This. If you fired a .357 thru the .40 barrel you may get lucky and just have it rattle down the barrel and exit erratically. Now think about that .40 caliber bullet trying to travel thru a .356 diameter bore at 35500 cup. What do you think will happen?

[Chief-7700]

So I already had a SigPro 2340 in .40....today I picked up another Sig 2340 in .357..since the mags are interchangeable I was curious as to what happens if you put a mag with .357 into the .40 and vice versa...well, I can rack it and chamber a .357 into the .40 but not the .40 into the .357...

So now I'm curious what would happen if someone chambered a .40 with a .357 round and pulled the trigger? Would nothing happen or would I get the big bang with ugly results? Anyone know? Surely someone must have done this accidentally before...

Might want to keep your ammo separated.

[pepsi2451]

The extent and severity could range anywhere from simple malfunction all the way to deadly catastrophic failure.

Does that make it clear enough?

yes, it should be painfully painfully obvious that you should only shoot ammo that your gun is chambered for. This is up there with "don't point a loaded gun at your own face and pull the trigger" in terms of proper gun handling as far as i'm concerned.

If you really have to ask about shooting the wrong caliber of ammo out of your gun - you very well may want to consider a hobby in stamp collecting instead of guns.

He asked what would happen, not if it was a good idea. I don't really know what would happen but I would think railroader is probably right.

Being the bottom half of your brass is 40 cal you would probably get away with. The neck might get resized up to 40 cal and the 9mm bullet would go rattling down the barrel. Mark

I definitely don't see anything good coming from it.

[RobG]

Might want to keep your ammo separated.

Excellent idea. Shoot one then put it and all the ammo away before pulling out the other

[CSACANNONEER]

WOW. Someone needs to learn a bit more about their guns BEFORE an accident happens. It's obvious that the OP needs to better educate himself but, no one has bothered to answer the question yet. The answer is that the bullet will bounce down the barrel and leave it in the general dirrection the barrel is pointing. It will not hurt the gun or the shooter but, there is no reason to do it. All a .357sig is is a necked down .40S&W.