Brink back team mate ammo request pings.

I've come across this same problem. The temporary way around it is you have to ping the ammo inside your inventory but if you don't have any then it's an actual problem because you can only ping your gun which in turn will only ping the arsenals. So if you don't ping before you run out of ammo you can't ask your teammates through in game options. 

Respawn Please fix this