I have a 9mm and .40 Sig 2022 I traded someone here long ago FDE grips for the black grips on my 9mm.
Recently picked up a .40 and it has the black grips on it.

Can I just swap the grips so the FDE is on the .40?

Yes. The frame of the firearm is the same between the 9mm and .40. You shouldn’t have any issues with the grips.

Excellent!

Can I drop a .357 Sig barrel in the .40 slide then rock and roll with some .357 ammo? Or is something else needed?

That, I’m not sure but I’m assuming it would work. Kinda like the way the P229 converts.

Might need a stronger recoil spring

Yes, you can drop in a .357SIG barrel and it will work just fine. .357SIG ammo will work fine in .40 mags, but not the reverse.

quote:

Originally posted by Black92LX:
Excellent!

Can I drop a .357 Sig barrel in the .40 slide then rock and roll with some .357 ammo? Or is something else needed?

Thank you.

Don’t really need to venture into another caliber but probably the cheapest way to get started.

In the event I ever run into a USP Compact in .357 I’ll be ready to rock.

quote:

Originally posted by AUTiger89:
Yes, you can drop in a .357SIG barrel and it will work just fine. .357SIG ammo will work fine in .40 mags, but not the reverse.

quote:

Originally posted by Black92LX:
Excellent!

Can I drop a .357 Sig barrel in the .40 slide then rock and roll with some .357 ammo? Or is something else needed?

SigPro 40/357 are the same mag. You can't use 40 in 357 p239 mags, maybe that's what you were referring to. 9mm mags would be reccomended if you put a 9mm barrel in your sp2022/sp2340. However, even then a 40/357 mag still functions at the range.