Last Wed. I started loading for a new rifle I got in 260. I loaded 42 grs of 4350 pushing a 139 Lapua seated at 2.80 OAL. It was averaging 2,830 fps. The temps were around low 70's. yesterday I shot those same loads and was averaging about 3,011 fps. Temps were aroun 68 with 60% humidity. I'm...