The problem I see is that your two groups with the same powder charge are not the same in any of your tests. How are you supporting the rifle during the testing? You need to make sure there is absolutely no way it's you messing them up before you think about using the results you see on paper. This means sandbags and as little contact between your body and the rifle as possible. If the crosshairs aren't completely steady on the target when you squeeze the trigger you are wasting your time. Your body should only be behind the rifle to absorb the recoil, you aren't there to hold the rifle during load development.
Depending on the case volume I make my loads in increments of 0.2gr-1gr. For example, in a small case like a 223 I make the powder charges 0.2gr apart, in a 308 I make them 0.3-0.5gr apart and in my 338 Lapua I make them 0.5-1gr apart.
As you saw in my "lucky at the range post" 0.2gr in a 223 case is noticeable and I was able to find the best load for a given powder in one range outing.
The ladder method also works well and one of my buddies swears by it and he is able to zero in on a good load in quite a few less shots.
Mystic precision has a great write-up on doing it and other reloading tips. http://www.mysticprecision.com/wp/category/tech/tech-reloading/
Good luck
Depending on the case volume I make my loads in increments of 0.2gr-1gr. For example, in a small case like a 223 I make the powder charges 0.2gr apart, in a 308 I make them 0.3-0.5gr apart and in my 338 Lapua I make them 0.5-1gr apart.
As you saw in my "lucky at the range post" 0.2gr in a 223 case is noticeable and I was able to find the best load for a given powder in one range outing.
The ladder method also works well and one of my buddies swears by it and he is able to zero in on a good load in quite a few less shots.
Mystic precision has a great write-up on doing it and other reloading tips. http://www.mysticprecision.com/wp/category/tech/tech-reloading/
Good luck
