Just learned that standard Talley rings will snug right up on a 3/8" rail. Their standard rings cost a lot more than their Rimfire rings, that I don't know about, may have to buy a set of the rimfire rings and try on the regular bases for centerfires, but they offer high, med and low which will do great on a 3/8" rail, and the standard screw locks are not that crazy expensive. Fit great and look good.