Fire the primary attack. The default fires Sandbox.BaseWeapon.Ballistics - spends a round, shoots the volley from Sandbox.BaseWeapon.AimRay with Sandbox.BaseWeapon.CurrentSpread, and plays the effects on every peer. Override for melee, projectiles and tools. Runs once, on whoever controls the weapon - the owning client for a held weapon (its hits reach the host as claims, see Sandbox.BaseWeapon.ShootBullet(Sandbox.SceneTraceResult,System.Single,System.Single,Sandbox.TagSet,System.Boolean)), or the host for seat/NPC/world weapons (damage applies directly).