Made Of Steel
Burris solid steel rings not only ensure accuracy, they provide an extra measure of confidence and peace of mind. Machined from a solid block of steel to exacting tolerance, each top and bottom are matched for strength and fit. Designed to handle any rifle and any recoil from rimfires to magnum calibers. Burris offers a wide selection in 1" and 30mm.
Big Book Catalog, Issue:71, Page:262
Sinclair, Issue:5B, Page:020
Sinclair, Issue:5B, Page:204
Measurements are from the bottom of the scope tube to the bottom of the ring: 1" Low .130", Med. .255", High .450". 30mm Med .205", High .330"
SPUHR makes separate rings for those who prefers them, the main reason would be because they are somewhat lower than the unimounts. The rings are available in one height only – 1” (25,4mm). They have a built-in level, that is somewhat smaller and not as visible as on the unimount. Dual vials allow the rings to be mounted for a left handed shooter. The separate rings do not come with any built in elevation. SPUHRs system for leveling the scope works for separate rings as well and the leveling kit is included with the rings.