Originally Posted by
DoubleBuck
I think I have experienced the patch problem, with my chrono, too. I was getting some speeds of '26' or '35', etc. I found several patches real close to the chrono, so moved it out from 13 feet, to 18 feet and they seem to not do that any more, but it seems like the speeds were fluctuating more, as well. I'm thinking about moving it to four or five feet, and try that. Maybe shoot higher away from the lenses. I've wondered about the smoke several times, too. But, I started covering the shades with a white tee shirt, too. So any smoke or patch will have to cross the lenses, within less than a foot above, to read them.
I have an RCBS chrono with a cable to the readout unit on the bench - I shoot at maximum cable length (20 feet)
always pick a spot under a shady tree to setup cuz this thing goes nuts if the unit is in sunlight or even light dappled shade.
I have also felt that sweet spot you talk about, with the high speed. Sometimes recoil will just feel like it was different. Not sure what that is all about. My rifle recommends a .015 patch. They are too tight. I use a .010 and they seem far better. But once in a while, I will get one that moves on the ball, and exposes an edge. I'm pretty sure that affects some of the accuracy.
darn right it does - cut the patches a bit bigger gives you more wiggle room
Maybe one out of 20, but still, it happens. Good luck with the experiments!