Prior to the lug's invention, bayonets merely stuffed into the muzzle's end from a tight-fitting stub, rendering the firearm virtually useless and certainly preventing it from being discharged. But by the late 17th century, this type of bayonet was entirely phased out and subsequently replaced with the socket bayonet, that slides over the muzzle with the blade offset to the side, just above or underneath. Bayonet lugs are usually located near the muzzle end of a musket, rifle, or other longarm barrel. The lug is occasionally placed on top of the barrel, if serving as the base of the front sight, or more often mounted to the side or bottom of the barrel.