[Parallex]

I think the only Callback for the one you are asking is

pawn Код:

public OnPlayerWeaponShot(playerid, weaponid, hittype, hitid, Float:fX, Float:fY, Float:fZ)

Well, It works when a player shoots, doesn't matter if it hit anything/anyone.

Maybe, these callbacks can help you:

pawn Код:

public OnPlayerGiveDamage(playerid, damagedid, Float: amount, weaponid, bodypart)

And

pawn Код:

public OnPlayerTakeDamage(playerid, issuerid, Float: amount, weaponid, bodypart)