NOTE: Remember that MGs do not expose this, since any bullets left are removed along with the bullet chain.
If this is implemented, please make it configurable. Not all weapons work the same way.
A reload/ejection movement (key binding) is also needed to eject the last bullet from the gun (e.g. SD ammo or tracers), which might be leftover from a different magazine after a tactical reload.
If you go even more realisic, include the requirement of pulling back the lever/carriage or to release it (depending on the weapon) after reloading when shot out, but this could be automatic (routine of the soldier).