I am acquainted with Sid Haight, the founder of S&K, now retired, who sold the business to the current owner. He advertised, for many years, that his ring-to-base design was through an arrangement with Conetrol. He never worked for Conetrol. Sid learned the tool/die trade locally and improved upon Conetrol's design, first specializing in cleverly designed mounting arrangements for military and obsolete rifles.
George Miller, Conetrol's owner who is around 90 years old these days, has always been most helpful with me and voluntarily discounts whatever I buy without me asking for same.
I've never had ring-marking issues with any of the many Conterol mounting systems I own. Ditto for S&Ks. I do prefer the simplicity and weight of the S&K design over Conetrol's.
