Check the other thread to see pictures. On the theory which seems most plausible right now, I'm pulling ammo to see if I double charged a round causing the cylinder to blow up.
First was re-calibrating my GemPro 250 and checking the weights against a different scale. All good
I weighed all of the rounds and came up with a variation of 373.4gr-379.75gr. A double charge would have been 8.8gr which is about 2.5gr over this variation. That is 373.4gr + 9gr = 382.4gr
Checking random Starline brass yielded a difference of 2.3gr from the same supply I used to load these. The brass is part of a 1,000 rd order from Starline.
I then pulled the lightest and heaviest to test.
Boolits variation was 4.0gr lightest to heaviest weight.
Powder variation: .05gr Weight from 8.75gr-8.80gr
I checked the powder as suggested. I pulled out the last fast powder I used which is ETR7. I shook up the Unique then poured a healthy amount on a piece of white paper next to an amount of ETR7. Both powders appear very close in looks but the ETR7 is gray and the Unique black. There is enough difference to be easily apparent under light. The unique from the pulled rounds and the bottle are uniform black so no mixing.
OAL are all uniform. All primers well seated. I also tried 18grs Unique in a case allowing for a variation in the powder charge to 9gr and a double charge. The case is almost full as in a compressed charge would be needed to seat the boolit. It is so readily noticeable that you can see it under room light easily. Could I have still missed it? Maybe but unlikely since I was using a
Lee Single Stage requiring each charged brass to be lifted from the holder then the boolit to be seated by hand then loaded and crimped by hand one at a time. Several steps from inspecting under a light to loaded to catch a double charge.
So...where does this leave me? If you take a worst case scenario and use the lightest boolit, brass/primer you still come out 35% or so under a double charge. Could a boolit with a worst case scenario double charge using the lightest brass/boolit combination be picked at random from a case of 100 and blow up the gun? I guess but that seems far fetched as so far nothing indicates a double charge was in the rounds loaded and that random string of bad luck, a 1 in 100 bad boolit choice using worst case brass/boolits still being under the heaviest loaded round in weight is next to impossible to fathom.
Next step is to pick 12 at random from the remaining and get out my trusty Blackhawk and shoot them over a chronograph to see if there are any velocity spikes or strange readings.