You sure can... check it out:
Command :
Ammo
Description :
Used to check how much ammo is left in a weapon.
Syntax :
UnitName Ammo "WeaponName"
UnitName is the name of the unit you are checking
WeaponName is the name of the weapon you want to check. Check the Weapon/Ammo Type List for valid ammo types.
Returns :
Number of rounds remaining in the weapon.
Example :
?(MyGuy ammo "M16" == 0):aP sidechat "Reload damn it!"