I found out that you can equip a companion with a new weapon and he will still have unlimited ammo as long as the new weapon is of the same style as the companions standard weapon.

I equiped Fawkes with the vengeance gatling laser making him even more deadly.

It did work with charon too, equiping him with the terrible shotgun.

--D.VADER 15:13, 26 July 2009 (UTC)