Dukemeister wrote:
. . . sensitive to perfect alignment of trajectory with sensor 1 and sensor 2 (How many ERR 2 I have with my Chrony drives me crazy).
Yes. I have a ShootingChrony, a Master Alpha. Early on, even after I mostly had it figured out, I was still getting the odd error or small string of them. Then I got a decent tripod from the thrift store for 12 bucks and mounted it on that. And I found a method. I almost never get errors anymore. I'll describe my method here.
Yes, the barrel, sensors and target must be in perfect alignment. I imagine that this may be tricky for shorter distances. I've done all my sessions at 17m and this alignment is rather critical. The chrony needs to be quite level, left to right and front to back on the tripod. And the rifle needs to be shooting through the vertical sweet spot of the chrony.
I place the rifle on it's rest, look through the scope and make sure it's pointing straight at the target. Then I shuffle the tripod a couple feet in front of the barrel, look back over the chrony at the barrel and quickly line them up in a general way. Then I go back to the rifle, make sure it's still pointing at the target. Then I sort of look over the barrel and sensors, at the target. It's fairly easy to see if they're all aligned or not. Then I'll go to the tripod and make small adjustments; I'll move the feet of the tripod incrementally, a few mm at a time if necessary, left or right. Go back to the rifle. I'll repeat this 2 or 3 times until it's correct. I used to have toothpicks taped to the chrony front and back on sensor-centre to help with this, but I don't need that anymore.
Setting up this way, I'm able to have long chrony sessions, multiple rifles and pellets. No errors. Nothing but fun. And efficient.
If I'm shooting through the vertical sweet spot, I can do a whole column of targets on the page without changing the height of the chrony or the rest. But if I finish one column of targets and move to the adjacent column, I have to make a small adjustment to the feet of the tripod under sensor 2. Just one little adjustment usually. The chrony session goes on error-free.
I think I've only done one chrony session to measure downrange velocity, some time ago. In that case, when I moved from one target down to the next in a vertical column on the page, I had to move the chrony down too, to avoid error. I may have got away with 2 targets before I had to move the chrony.
Hope this helps.