hey fellow,eldeguello,is headed the right way,but i add to that.big game are0.015 ins to 0.020 ins off lands and grove.ground hog loads are 0.010 ins off.
the reason big game you could be in snow or rain or ice to close could cause to much press,ground hog no bad weather,closer to lands and grove the better they group
also after i find the best 0.5 grain load,i then start loading in 0.2 grain from 0.75g before the best 0.5 grain load to 0.75g after the best 0.5g load.
(exp) lets say your best load with 0.5 grain change is at 42.0 grains i would back up to 41.2 grains loading in 0.2 grain change up to 42.8 grains. and then shoot for best group. i shoot three shot groups to test
i have taken stock firearms that would shoot only 3 in groups with factor loads and doing this will now shoot right at 0.25 in groups at 100 yds.
hope this helps.wolf1