1911 .40 S&W to .357 Sig - Anybody done one?

[nicholst55]

I've got a Springfield in .40 S&W with the ramped barrel and I've been toying with the idea of buying a .357 Sig barrel for it (because I can). I'm hoping that the .40 S&W mags will work for the .357. Bar-Sto and Nowlin both make 'drop-in' barrels, so right now all I need is money. :p

Has anyone tried a similar conversion? Any recommednations or tips? I'm kinda curious about what weight recoil spring I'll need, if anyone can offer any insight. :confused:

[Hawkmoon]

Your question does not relate to a conversion kit, and therefore it belongs under the Gunsmithing forum area, not the area for discussing conversion kits.

I am taking the liberty of moving the thread to the appropriate forum.

[Azrael256]

I've never tried it, and I can't offer any specific tips, but I REALLY want to know how it goes. If I ever have a 1911 in anything but .45, it'll be .357Sig. As for the recoil spring, you might order up a "calibration pak" from Wolff and go with the heaviest recoil spring that will still function method. If'n I was a bettin' man, I would say that the standard spring will probably cycle just fine, but I don't know enough about .357Sig to know if it's going to recoil harder than .45 and batter the gun.

I do know that my bro-in-law has a Sig 239 in .40. He went to pick up a .40 magazine and got one marked .357Sig. It ran just fine, and when I called the gunshop, the fellow on the phone said the magazines were interchangeable. I'm fairly certain that the case head is the same size, and the OAL is either the same or close enough. I'd guess that it should work just fine with the .40 magazines.

[nicholst55]

The thing that has me wondering about the mags is how Glock handles this, and that may just be marketing. They claim that the .357 won't feed properly in a .40 mag because of the follower angle, and they specify a separate mag. That said, I think a lot of people are using .40 mags in their Glocks.

I wanted to buy the gun in .357 Sig to begin with, but nobody offered one. In fact, the only .40 S&W 1911 that I could find was this one Springfield, with the ramped barrel. Having the ramped barrel reduces the choices of barrels down to only Nowlin and Bar-Sto - not bad choices to be sure, but just the same.

I think having a .357 Sig 1911 will be a hoot! It will have to wait until I'm done playing in the sandbox, though.

[sleepertib]

It is probably just marketing. The .357SIG is simply the .40S&W necked down for a 9mm bullet. I'm not too surprised that the magazines are interchangeable.

Springfield is not the only one offering a .40 1911. STI offers a few that I know of, along with Para-Ordinance, Dan Wesson, and a few others. Springfield makes a pretty good one, though. It'll be interesting to see how yours turns out.

[Adam T]

I have a Sig Pro 2340 which came with interchangable .40S&W and .357SIG barrels. The same mags are used for both, and in fact, the mags are actually marked for both rounds. The same recoil spring is used for both rounds too. Obviously your mileage may vary since we're taking about different guns, but I thought I'd let you know.

The .357SIG is a pretty hot round. Seems to make a bigger bang than the .40S&W. I usually keep it chambered with that.

[Azrael256]

They claim that the .357 won't feed properly in a .40 mag because of the follower angle That makes some sense, but it seems to me that it would be the other way around. I would think that the .40 mags would have a steeper follower angle (assuming that it needs to be different), and that the .357Sig would work just fine on the steeper angle. But, I'm not a Glock armorer, so there's likely something about their feeding system that I don't know. Just a thought, really.

[SIUFLSR]

I have the Glock 23 and I use the 40 mags with my 357 barrel, no issues. Glockmeister.com has a section on conversiosn for those guns and they say the same thing. Can't wait to see how your conversion works out. New ways for me to spend my money, I'd almost run out.