Companion ammo (Fallout 4)

Companion ammo is used in companions' weapons in Fallout 4.

Gameplay
The ammunition companions use is infinite and has a non-playable tag. It is the classification of ammo that the companion's default weapon uses, and always is used when not having any weapon equipped.

Active companions equipped with any melee weapon (their own or provided by the player character) do not consume any ammo at all. A companion can pick up a weapon and ammo on their own and use it when fighting.

The only way for a companion to spend "real" ammo is when all three of the following conditions are met:
 * 1) The companion has a weapon equipped in their inventory (a weapon that can be seen equipped in their inventory when trading with them).
 * 2) The companion has at least 1 (one) ammo that can be seen when trading with them used by the type of weapon equipped.
 * 3) The companion is the current active follower.

If all three conditions are not met, or at least one of those cease to be true, the companion will stop consuming "real" ammo, and as the active follower, will switch to their own default companion weapon that uses companion ammo. But if not currently the active follower companion, they will carry on with the same game mechanics for weapon and ammo that apply to the settlers.