Thread: 1 shot groups (cold bore challenge)

Originally Posted by zeropak

When you say cold bore. Is that bore clean or still fouled from previous sessions. Personally I have noticed that with all the rifles I regularly shoot (2 x .223 and 2 x 6.5CM) the first round through a cold, clean bore always has a slightly lower velocity than shots subsequently fired in the same session, around 30 fps. The POI at 100m doesn't seem to be affected but I guess the lower velocity would start to make a difference at longer ranges

I have data from dozens of groups and several different rifles and there's no trend for the first cold shot to have a velocity that is outside of the normal spread or that is higher or lower. That said this is from fouled cold bores mainly rather than scrubbed back to bare metal.

Originally Posted by gimp

I have data from dozens of groups and several different rifles and there's no trend for the first cold shot to have a velocity that is outside of the normal spread or that is higher or lower. That said this is from fouled cold bores mainly rather than scrubbed back to bare metal.

Ok I would seem then that the lower first shot lower velocity has to do with the clean bore and not the cold bore.