I jus got a load sorted for my 6.5x57 using the 139gn Privipartisan bullet
I loaded up 10 139gn SPBT Privi bullets at the starting load of 42gn 2209 to get the scope dialed in but that only took 4 to have it sitting 1 inch high at 100 yds. You can see that as shot one in the pic below.
My ladder test loads were in .4 gn increments from 42 up to 46.4 which according to QL would give me 2812fps at 57K psi.
Normally I like to do the ladder test at 200yds but thought I would get a reasonable reading at the shorter distance and it proved to be the case. You can see that shots 1 through 7 are hitting high which means that the bullet is leaving the barrel at the top of the oscilation, shot 8 is at the bottom of the vibration swing but shots 9 through 12 are in the center where the barrel is "at rest" (so to speak). There is every possibility that there is some shooter induced windage error as this is not a target trigger but even so to have 11 of 12 shots go into 1 1/2 x 1 5/8 with a varience of 4.4gn of powder is a reasonably good result (or at east I thought so). I have loaded the remaining brass at 46.2gn which should get me right on 2800fps and that is not a bad velocity for the 139gn bullet which should deal handily with the goats and be good to go for deer up to wapiti size if the ocassion arrises.
Shots 10, 11 and 12 (with different powder charges) have gone into a 1/2 inch so confidence is reasonably high that this build has been a real sucess and taking just 12 bullets to get a load dialed in is one of the advantages of the ladder test. Normally I would do a number of groups with the loads from 10 to 12 but the consistency of the shots allows me to expect that this is an excellent node so the chosen 46.2 gn is set for this bullet.