Sig 239 Mags - does .357 work in .40?

[JDOV SS]

I have been reading alot of posts but can't find a definitive answer for this question.

Can you load .357 sig into .40 S&W mags and will it load without problems?

I just purchased a .357 barrel for my P239 and was hoping to use the .40 mags. Has anyone done this?

 

[mikem317]

I think they're two separate part numbers from Sig Sauer for the P239; which suggests that there's no interchangeability. I know the P229 magazines are interchangeable though.

 

[appraiser]

In every other gun I have ever seen with a conversion barrel the .40 mags will take .357Sig ammo. .

the reason for the different part numbers may be as simple as the markings.

 

[Jarhead]

Yes it will work.
But it won't work the other way around. You can't put .40 in a .357 mag.

 

[Jose]

Yes it will work.
But it won't work the other way around. You can't put .40 in a .357 mag.

Why not? The cartridge cases are the same from the shoulder back.

 

[drgrant]

Why not? The cartridge cases are the same from the shoulder back.

The Sig P239 .357 mag is different from the .40 mag for the same gun.

It sounds dumb, but true.

I have no idea, if .357 sig will work properly in the .40 mags.... it -should- by
logic, but you have to wonder why they made them different to begin with.

-Mike

 

[Dick]

I have a SIG P239 with both the .357 SIG and .40 S&W barrels, and with both types of magazines. Jarhead is correct - the .40 S&W magazines will handle .357 SIG, but not the reverse. Responding to Jose's question, the .357 mags are shaped to follow the cartridge case shoulder, so can't take the .40 cases, which don't have the same shoulder.

I can't answer the question of why SIG chooses to make a magazine specific to the .357 when they will function through the .40 mags - presumably there must be some advantage to it, but I've never had any feeding problems running .357 through my .40 mags.

 

[Jarhead]

Jose---- The lips on the front of a .357 mag are closer togetherto accomodate the smaller diameter of the neck/ bullet.

 

[JDOV SS]

Thanks guys! This was great information and will save me some $$ on mags!