Mr. Chrony comes by my range from time to time to test. He has a long board with a fancy chrony in the middle and 7 of his units all mounted in line.
he shoots these with a 22, a 308 and a 243. The accuracy of his units is excellent. Some will be up to 20 fps faster or slower than the lab unit, but they are consistent withthe difference, so therefore, accurate for our purposes.
I smiled at the comment about shooting a Chrony. Blew up 7 of the suckers, so far....