.357 sig is a very oddball caliber that not many people at all have weapons for. Looks like they don't want their ammo to be able to be picked up and used by anyone else. Guess their guns will have to also be liberated on the battlefield.

FYI .357 sig is a .40 caliber casing necked down to hold a .357 caliber projectile/bullet. Only used in some Glock handguns, it is a proprietary Glock caliber in fact.