The most common scope mounting system is called a Weaver style. These utilize the flat rails with crosswise slots in them that you see on everything from rifles to shotguns to handguns. The Weaver style bases are 7/8 inch wide and accept Weaver style rings. Most manufacturers make Weaver style rings. There are crosswise protruding rails, a type of recoil lug, running underneath the rings that fit into the corresponding crosswise slots in the Weaver bases. This prevents movement fore and aft under recoil and abuse. The bases may be one or two pieces and be made of steel or aluminum. Weaver rings are detachable from their bases with the scope still in them, and can be reattached without a major loss of zero. The scope can be reinstalled on a different gun, or removed for gun maintenance or travel. Swapping scopes for different purposes is also facilitated.![]()