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.