AKBman
Well-Known Member
Had loaded up some of the 210gr LRAB bullets in Norma 300 Win Mag brass with CCI 250 primers to light off the charges of MagPro,was also shooting some 200gr Partitions strictly for groups. The 210s and MagPro caused me no issues, the Partitions which I shot an hour later sure did. When I started shooting, the temps were in the low 90s, I shot the 210s, and was very pleased with the results for having no load development, they put 5 into less than 1.5" at 200 yards. The first 200gr Partitions I shot were loaded over two different charges of RL 26, bu this time the temps were just reaching 100, they put 10 shots into a little over 2" for the two different charge weights, at this time I was only able to shoot 2 shots before allowing the barrel a substantial amount of time to cool, I was also shooting my 375 Ruger loaded with cast bullets for groups at 200, shot a little over 3" at that range. By the time I got to the 200gr Partitions with the MagPro load, the temp was reading 109, I fired 1 round, got settled and loaded round two, I should have checked the barrel I got distracted for a few seconds, and when I fired the second round, the primer popped out when the case hit the bench, this was a once fired case. I ended up having to wait 5 minutes in between rounds, and the Magpro group with the 200s was 2 1/2" for 5 shots. When I packed up to leave, the temp read 112, the last rounds I fired were 260gr Partitions from the 375 Ruger, and even though I worked the load up when the temps were in the 50s, the change in POI was less than .75" vertical, I use RL 17 in it almost exclusively. I think in the future, I will be investing in more of the temp stable powders, while they are still affected by 50+ degrees of temperature swing, it is very manageable, the MagPro, while giving me excellent accuracy, is not my way forward, I don't want to have a summer and winter load.