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Dumb Question: Will a .357 SIG also feed/fire .380?

8K views 11 replies 11 participants last post by  kazzaerexys 
#1 ·
I just figured that since a .357 Magnum will fire .38's......

...or is there a conversion kit of sorts to make it do so?
 
#3 ·
The Sig Sauer P250 is an exception. It will not however take .380. Slides and barrels are interchangeable making this one of the most versatile semi-autos available. It can be fitted for 9mm, .40, .357 Sig and .450 Auto.
 
#5 ·
NO it won't fire 380's. These guys have conversions for 40 and 9 for your 357 Sig. Since a 357 Sig is a necked down 40 S&W, it's an easy conversion. Converting to 9 requires a magazine and spring change as well as the barrel. Going down in size works, but if you have a 9 and want to convert to 40 or Sig you have to change slides and that gets more expensive,

https://www.efkfiredragon.com/index.php
 
#6 ·
Well...it will almost certainly FIRE the .380 from the .357 Sig barrel...

I've seen .40s fire 9mms accidentally, so I would think that the .357 Sig would fire the .380. Given the difference in length of the two cartridges, I would think that either damaging your gun or causing a squib-like bullet in the barrel situation would be pretty likely.

When a 9mm fires from a .40, it sounds like a loud squib (primer only). The case forms to the chamber and splits, and the gun does not cycle. Believe it or not, the guy hit the target at 7 yards. In that case, the cartridge is actually longer, but a full millimeter smaller in diameter. I don't think you'd be as lucky as he was.

Dan
 
#7 ·
as others have said....no

if you're wanting to shoot less expensive ammo at range, etc then get a 9mm conversion
 
#9 ·
Dumb Question: Will a .357 SIG also feed/fire .380?
That question is not dumb, dumb would be asking why the .380 round messed up your .357sig gun when you tried to fire it....finding out before you try is very smart.....I say well done.
 
#12 ·
Not that I can think of. The feeding and chambering geometries of semi-autos are just too particular to the intended round. Revolvers generally fire rimmed ammunition (think of the big rim around the base of a .38 Special or .357 Magnum round) that allows the base of the round to sit against the back of the cylinder. As long as the round doesn't extend out past the front of the cylinder and the bullet is the right diameter for the barrel, you can theoretically fire the round.

Most semi-autos fire rimless ammunition, where the base of the casing is the same diameter as the body of the casing. Then the round spaces on the shoulder of the cartridge, where the brass crimps to the bullet. Now working backwards along the casing, everything has to fit just right for the barrel to lock up and the firing pin to hit the primer.

Revolvers that use rimless ammo use moon clips, which (more or less) make rimless rounds act like rimmed rounds.

The interesting case would be the few autoloaders that use rimmed ammo, like the Desert Eagles that fire Magnum rounds. So, is it even theoretically possible for, say, a .357 Magnum DE to chamber and fire a .38 Special? I guess that comes down to this: does the DE use the rim to chamber the cartridge (making it internally like a revolver barrel) or do the DE chambers still headspace on the shoulder?
 
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