OnWeaponChange

From the Scripting Manual
procedure OnWeaponChange(ID, PrimaryNum, SecondaryNum: byte); Parameter Info: ID (Byte): Player ID of the player who has changed weapons. PrimaryNum (Byte): Primary weapon number SecondaryNum (Byte): Secondary weapon number Description: This procedure will be called every time a player switches weapons, drops a weapon, picks up a weapon, and when they pick a gun from the respawn menu.