Thread: 1 shot groups (cold bore challenge)

I have noticed the velocity increases after the first shot on a cold clean bore, it seems to increase over the next two to three shots then it settles down. The spread in velocity from the first shot to the last (3shots) is around 30-40 fps. I read that the carbon left in the barrel helps increase the velocity to a degree. Over normal shooting ranges it should alter points of impact to much.