These are not new. I had them mounted on ZCO 527’s. We extended the range out to 500+ yds for Rimfire, and I needed to add the 20moa 6602 over the 50 MOA area 419 rails on my Cz 457.
I can get out to 500 yds with no holdover needed getting the full 35 mil of scope travel with basically a 70 MOA total elevation.
I still have the other 6001 Spuhr mounts on my centerfire rifles since they don’t need that much overall travel the scope doesn’t itself provide for.