I've got the Redfield high rings mounted on the lightfoot device now with the Nikon 3-9. Is there any way to bore sight this thing without a boresight device. I usually can look through the barrel to bore sight rifles, but this one is impossible to do that way. Is my best option to take it to a shop and have them do it? It's a bit chilly to spend much time at the barn range figuring it out and wasting bullets.