Originally Posted by CJOttawa
When used correctly, I've had half a dozen RadarChron (mini yellow) chronos, one big RadarChron ROF, an X-Radar, Big Red, and ToughChrono (big yellow, similar to Big Red) read EXACTLY THE SAME.
Make sure the sensor area is clean, there are no obstructions or other objects (paint, rain etc) to interfere with the signal and even the little handhelds read +/-1fps.
This is kind of what I was suspecting. But I'm still perplexed as to what caused such a huge variance. 50 fps seems like a huge jump to me when the differing factors seemed pretty negligible. Yes, I was shooting different paint, but I adjusted the sizer for a very slight underbore, just like I always do. Would a 200 ft altitude change make such a difference? Am I missing anything else here?