relative ease of machining a reliably straight metal bar, dovetail rails pretty much eliminated the misalignment concerns of the screw-and-hole scope rings. Most dovetail rails are made by cutting triangular grooves into the receiver top, but there are aftermarket rails that can be installed with screws into the aforementioned scope ring holes. The top of receivers featuring an integral dovetail rail can feature shape connection drillings that function as one or more recoil to prevent undesired backward and forward sliding movement. Some manufacturers provide integral bases on many of their firearms; an example of such a firearm is the Ruger Super Redhawk revolver. The most commonly encountered mounting systems are the 3/8 inch (9.5 mm) and the 11 mm dovetail rails (sometimes called "tip-off mounts") commonly found on rimfires and air guns, the Weaver rails, the mil-spec MIL-STD-1913 Picatinny rail (STANAG 2324), and the NATO Accessory Rail (STANAG 4694). Ruger uses a proprietary scope base system, though adapters are available to convert the Ruger bases into other Weaver-type bases. Mounting rails European telescopic sight manufacturers often offer the option to have mounting rails underneath the sight to provide for mounting solutions that do not use scope rings or a single scope ring around the objective of the sight. These rails are an integral part of the telescopic sight body and can not be removed. The mounting rail permits the telescopic sight to be securely and tension-free mounted at the preferred height and correct distance from the shooter's eye and on different guns. There are several mounting rail systems offered: Standard prism, also known as the LM rail or 70° prism rail Zeiss rail, also used by Docter, Leica, Minox, Steiner-Optik and Meopta. Since 2016 also offered by Schmidt & Bender under the name LMZ (Light Metal with Z-rail) on some of their hunting telescopic sights. Swarovski Rail (SR), also used by Kahles (a subsidiary of Swarovski) Schmidt & Bender Convex, also marketed under the name LMC (Light Metal with Convex rail). The traditional standard prism mounting rail system requires to have the mounting rail drilled from the side for fixture screws. The more recent proprietary systems mainly offer aesthetic advantages for people who have problems with redundant drill holes in the sight in case it is used on different guns. To avoid drilling the mounting rail, the proprietary rail mounting systems have special shape connections machined in the inside of