Regarding the receiver grooves, the standard is 3/8" and grooved Kimbers are 11mm. For options, you can use original Kimber rings or old Warne Premier rings, but both are elusive to find and expensive. Leupold still makes a steel rimfire ring with the 11mm spacing and the correct radius. Warne makes a rimfire ring that fits both 3/8" and 11mm grooves by flipping over the clamp. The best option is the Talley rimfire ring made for Anschutz rifles, 11mm, radiused and vertically split like the original 2nd generation Kimber ring.
