If your gun was shipped in 40 you'll find that the fixed sights are geared for the 165 grain bullet. Put the 357 Sig barrel in and you will find the bullet strikes about 5 inches low.
If your gun was shipped in 357 Sig and you have fixed sights yu'll find the opposite.
MMC is now making adjustable combat sights for both of these weapons.
I have them on a USP9mm and they are aces.