Received the M-600 from Bushmaster on Tuesday as scheduled.
Nice scope. Optics are very clear and sharp. Mount is built like a tank and the overall quality is very good. The "framing" grid marks for the auto ranging feature are extremely fine, but the quality of the optics makes them sharp, defined, and easy to see and use.
I mounted the scope on a 20" flat top Bushmaster, and took to the range yesterday. Scope was very easy to sight in. They recommend 200 meter sight in for proper operation of the bullet drop conpensator feature, but do give a chart for sight in at 100 meters. I was shooting 100 yards, so had to use the chart to adjust impact for that range. After all adjustments I shot a 5 shot group covering 1.75 inches which is pretty good for me.
Next step will be a coyote hunt to see how the auto range feature actually functions.
The only negative I see so far is the weight. The scope/mount is a little on the heavy side, and does add weight to the rifle.
I am very pleased with the scope.