Any ammo can he will run into has one in each bandoleer. They arent hard to stumble upon.
Kinda falls into a grey area of "parts thereof", there are kit lists out there that say you should have one, but youre technically supposed to toss them into the salvage bin after they are done being used.
Tell him to ask his log staff or weapons techs. Or just ask around his unit. If that fails, PM me, I'm sure I have one or two somewhere I can send him through DND mail. If its not going to a soldier, I'm not giving away DND kit though.