I did a search but came up empty.

When you are shooting to test load development, do you discard your cold bore shot?

I ask this because I have noticed that my proof CF 308 barrel has a tendency to send the first shot almost 2" up and left from the rest of the shots. It is so consistant that I can use Kentucky Windage to correct for it most of the time.

Yesterday I tested some 155 TMKs and some 195 TMKs using Varget and BLC(2). I ran the 155s first and got some incredible groups and perhaps the best SD of my life....5! The lowest and highest charge weights shot the best, .301 and .515 respectively. However, on that first shot I did not think to correct for the cold shot and it was a full 2" high and left.

After finishing that string I let the rifle cool for an hour and repeated with the 195s but did compensate for the difference. Boom, it landed dead into the bullseye.

In the future I may just fire a plinking round to settle everything in before proceeding.

I switched to the AB Quantum app with the calypso mini AB and instantly have shot 10% better in PRS. It feels like switching from DOS to Windows 11. If you don’t already own a kestrel 5700 Elite ($769) you can buy the Calypso mini an ($315 Walmart) and pay $29.99 a year for the Quantum pro app.

What am I missing here?