Units Sharing Ammo - Too Weird a Concept?

[Imp]

Its very rare infantry run out of ammo anyway & I do not want ATGM teams sharing or even in most cases units swaping RPG ammo.
Has 2-3 shots left & gives some away now he has no extra shot at improved accuracy or nothing left now the target has used up its area defence system.
Guessing your talking vehicles, send the empty guy back to resupply why would the guy who also has ammo pull out of the line to & leave a big hole instead of defending his rear as he goes for a reload.