May I ask, are you looking for velocity or smallest group. Your powder charges seem to be very close as to powder charges. If looking for smaller groups which I would be doing then shoot your loads for the smallest group and then chronograph THAT group. I doubt with your small powder charge variance the velocity will be much different and you will have the smaller group. You seem to be going to a lot of trouble with maybe no end in sight. I wish you well.I have recently acquired a Magneto Speed Sporter and have been using it quite extensively. All for numbers for reloading of course. Over the past month I have shot many different loadings with different powders and bullets and have also repeated many to try and verify numbers..
Here is my dilemma, I am getting random shots that are just way out of the ordinary with absolutely no rhyme or reason that I can pinpoint...
I will normally load 12 each of the loads I want to test and then also load 3 separate weight groups. So like this; 12 ea of say 23.0, 12 each of 23.2 and 12each of 23.4.. I will then shoot them round robin is three shot groups at a single target with separate bulls for each one.
Shoot 3, move to the next,and shoot 3 and then move to the next and shoot 3.. After those I will repeat the process for a total of 4 rounds of 3.. All the while recording the shot speeds in order.
What I am finding is that in almost every three shot group there will be one shot that is extra ordinarily higher or lower than the other two. and there is no pattern that I can find. It can be the first shot, last shot or the second shot. Many times the shots will be within 10/15 fps or they at times match, but there is almost always one that is way out, sometimes by as much as 100fps!
My reloading practices for this have been meticulous. All brass the same headstamp,straight with no dents or deformed mouths. All sized and checked at the same batch, all trimmed at the same time. Every powder charge is check weighed on a beam scale and trickled up.. I have now just loaded some tonight and this time I tried it with annealed brass but of course I have not shoot this yet. I have also tried loading these loads to different length with no improvement.
Anyways I cannot think of what to try next. I have even tried more time between shots to see if this was a heat issue and it doesn't appear to be that either.
Not looking for perfection just to try and lower this Extreme Spread. If I could get consistently below 50 I would be extremely happy.