From Garry's Mod
Returns the sequence enumeration number that the weapon is playing.
This can return inconsistent results between the server and client.
Issue Tracker: #2543
This will return the ACT_ENUM that is currently active for the weapon.
local wep = Entity(1):GetActiveWeapon() if ( IsValid( wep ) ) then // Makes sure that wep exists print( wep:GetActivity() ) // Prints the sequence number end