A "long range" shot for me is 200 yards. At that distance even a .17hmr shows up just fine with my spotting scope. And when I am using the .50 and .54 cal muzzle loaders those holes show up really well!

I understand the idea of your system and when matched with a chronometer I can see the appeal it would have for some.

Good luck with your idea. I hope to see your target at a gun shop someday. It sounds interesting.

Peace.