[ThnkFrst]

I would make sure that your 9mm frame has a "40/357" locking insert (I think they all do).

The finish on the new 357 slide will black Nitron and, therefore, different than the Legion frame and will lack the front serrations (unless you get an Extreme, TACOPS or EE model) and Legion logo. But I don't see any flaws in your logic.

 

[chinch]

Yes the frames are the same in regard to caliber can accept any slide or xchange kit.

How Sig sells them in retail is simply based on what caliber (slide & barrel they preinstall) and what feature (grips, SRT or not, beavertail, sights, etc.) they feel is most marketable.

 

[Malicious Compliance]

Yes, the 357 slide will fit on the 9mm frame. One consideration I'd point out is the fit of the slides on the frame will be different from one another, resulting in different wear patterns between the two slides on the frame. If it was a steel frame, I'd be less concerned, however, with the Legion alloy frame, something you want to be aware of.

 

[sigsrok]

Welcome from PA!

I would call SIG Customer Service first. They may have to "fit" slide to frame.

 

[chinch]

Welcome from PA!

I would call SIG Customer Service first. They may have to "fit" slide to frame.

Sig xchange kits are not "fit" to the frame for any given model. They just fit simply because the Sig tolerances & quality allows for it.

 

[Malicious Compliance]

Sig xchange kits are not "fit" to the frame for any given model. They just fit simply because the Sig tolerances & quality allows for it.

SIG will fit a slide to the frame, if I was interested in running a different slide on an alloy frame, certainly a service I would consider. Because of the tolerance stacks involved, the initial fit can be a bit loose or tight, SIG will address this, if one is so inclined.

 

[chinch]

SIG will fit a slide to the frame, if I was interested in running a different slide on an alloy frame, certainly a service I would consider. Because of the tolerance stacks involved, the initial fit can be a bit loose or tight, SIG will address this, if one is so inclined.

Maybe my terminology is incorrect.

When you buy a Sig x-change slide/barrel/spring kit for a Sig226 for example it's made to FIT ANY 226. No "fitting" is needed for accurate & safe use keeping full warranty 100% intact.

Now if some humans want more than that and Sig offers something extra for standard production firearms great even better! I can't comment on that.

FWIW I exchange slides at almost every trip to the range with my 226 SS or Alloy. All good. I also expect wear & maintenance of anything i own (car, firearms, etc.)