I was outside in the shop, playing with loads for the cowboy shooters. I set up the chrony to test data, and the data was all over the place.
CFDA publishes a handy data sheet, but there has to be more than one powder that's suitable and I was playing with some powders that are already on my bench.
I've been a handloader for four decades and I'm pretty confident in my technique. I understand SD and VMD, and I know how to interpret velocities When you're working down in the low-pressure that wax bullets necessarily put you in, consistency is the key, and I know how to be consistent.
I'd load five cartridges, looking for an average muzzle velocity of 750, and those five would be all over the map. 721.2, 9715, 167.3, 50.61, and ERR. Just dam, what's going on? Just about the time i was about to lose my cool, I realized that lighting was the problem. The sensor couldn't see the bullets. I tried some known loads, and got the same type of data. It was all garbage.
I went to YouTube and that data is all over the map, too. Lots of low-cost alternatives, lots of high-cost alternatives, but it gives me some ideas.
It's frustrating as hell to set up equipment, run the very best test possible, and get data that is garbage.
2 comments:
Dude, move your chrono further from the muzzle. You are seeing powder grains instead of bullets.
What kind of chrono? And what kind of lighting? I've read in the past of folks having problems with light-sensing chronometers under fluorescent lights. And I recall one member on the old GEnie Outdoors roundtable setting up a clean white quality sheet like a ceiling tarp a few feet over the chronograph with portable incandescent lighting (this was pre LED, don't know if LEDs might have the same issue). Similar to how portable photo booths work t provide shadowless/directionless lighting.
A lot of LED lights use PWM controllers for dimming. If your lights are LED instead of fluorescent and don't just run straight on or off (dimming or level controls) then they're almost certainly flickering at a high rate to control brightness. That could have fun effects on a light sensing chronograph too.
Final thought. Wax bullets are white or translucent, aren't they? Even after firing/while in flight they may not have discolored much. Maybe mixing some graphite or other darkening agent into the wax might make a difference?
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