I think it was the light! I once was developing a load for my Ruger No. 3 in .30/40 Krag, using 200-grain Nosler Partition bullets and old H205, a powder which gave much higher velocities than any other powder with aceptable pressures in medium-capacity .30 caliber cartridges. Imagine my amazement when my Oehler chronograph told me that my top load was producing an average of almost 2800 FPS for a five-shot string! I went to my loading bench, pulled the rest of the cartridges and verified the powder charge. It was right on! I reloaded the ammo, and went back to the bench and tested the stuff again. This time the chrono said the average velocity was just a bit over 2550 FPS, exactly what I thought it should have been.

The first string that gave the high speed readings was fired early in the morning, about an hour after sunrise. The next test was at about 11 AM. I concluded that the sun's position in the sky (it was a clear day) had resulted in the false readings. Every time I have tested that old load since then has given me the 2550 velocity. Too bad! I think a .30/40 Krag firing a 200-grain bullet at 2800 FPS would be very cool!

one way to track down what happened is to set that case a side, mark it so you can track it. in a 100 round lot of brass i have had a couple that were out of the main group "a flier". i use them as foulers.

once due to a case length beeing .002" longer than others in the same lot. the die was adjusted in just enough that it would start to roll crimp.

with my chrony ever now and then i have a extreme change in velocity and can not find any real reason. maybe 100 to 125 f/s.. 200 is a bunch.

waht pressures are you getting with that Krag load???

I have a 1898 Krag I load mild loads for with a 160-180 bullet