When finished, I had three shots on each of the five targets, BUT (!)... I don't look for the tightest group of the five and call that my load.
Here's what I do instead, and I'll explain why later: I look for the three groups of the five that come the closest to hitting the target in the same position. I noted that in this case, the three groups from the middle of the string were the ones which happened to hit the same POI, (all within about a 3/4" overlay, and all at a 2 o'clock position with relation to the bull) with the 39.2 grain group hitting low and left from that common POI by an inch. The 40.4 grain charge, in addition to moving high and right of the common POI for the three center charges, opened up in size to about 7/8". The 39.2 grain charge shot just under 1/2", but as I said, it wasn't near the common POI that the 39.5, 39.8, and 40.1 charges shared.
So I concluded that the best charge for this application was 39.8 grains of IMR 3031. This was the charge that would allow 39.5 grain charges and 40.1 grain charges to group right with it.
Why would I want that?
Well, variations in brass cases, powder lots, outside temperature--and other things can cause your load to increase or decrease in pressure. With the OCW load, you're covered for a significant amount of pressure differences that may come into play. If I'd gone with the 39.2 grain charge (the sub 1/2" group), a *slight* rise in pressure, brought on by an odd brass case or a hot day, etc., would have resulted in a 1 MOA deviation high and right of my POA.
