Life and a few projects has been getting in the way of definitive load test but with a friend from down south coming to join me for a hunt into the high country next week, today I thought I had better get out and sort a load for the 6.5x57. I had 123gh A-Max, SST, 120gn TTSX and 139gn SPBT Privipartisan bullets and chose to go with the Privi bullet. I loaded up 10 at the starting load of 42gn ADI 2209 (H4350) to get the scope dialed in but that only took 4 to have it sitting 1 1/2 high at 100 yds.
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 9to 12 are in the center where the barrel is "at rest" 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 accasion 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.