Sorry I thought we were talking about barrel wear
Do we all end up at the same place though? Or is that just a thing handloaders say to play nice lol
That's my point with hunting rifles about a 3 shot group being representative and as you said a shot is a shot, weather you pile 30 rounds in the same spot on a target or you shoot several 3 shot groups you are still getting the same data, if Im using an F-Class rifle where you will be shooting 20 shot strings then you would want to see how the barrel reacts with larger sample size,
lets take my 7-6.5 PRCW, there was no company data anywhere so I used F-Class Johns recommendation of 55.5grs of N555 as starting point with a new barrel, after the first range trip I worked up in .3gr 3 shot groups using 175gr Berger Elite Hunters from a 26" barrel
56.1 avg vel 2812- 1/2" group
56.4 AV- 2832- 1/2" group
56.7 AV- 2850- 7/8" group
57.0 AV- 2864- 7/8" group
57.3 AV- 2866- 3/8" group
2nd trip I continued from 57.3grs in .2gr increments as I was being cautious without having data,
57.3- 2880- 5/8'
57.5- 2890- 1/2"
57.7- 2898- 1/4"
57.9- 2911- 5/8"
58.1- 2917- 7/8"
so I picked the 57.7 load and played around there 57.6/57.7/57.8 and settled with 57.7 which has been extremely consistent with velocity/accuracy, played with the seating depth a little and settled on 3.082" or 2.333" ogive
If I do my part its shoots a consistent 1/4" 3 shot group at 100 yards and an inch or less at 292 yards, after about 200 round my ES has never exceeded 12fps with that load
I also use the same load in my other 7-6.5 with a 23" barrel and it prefers 2.995 so a lot more jump to get the same accuracy velocity has settled at 2855.
so looking at it you would know better Mark is that OCW or OBT as the groups start at 1/2" then increase then decrease then increase,
Im sure there's an easier/quicker way to get there but I like to see the bullet holes on the target.