John, I tested my Pro Chrono against a pals 35P and there wasn't more than single digit differences between the two. One of the things that makes a difference on mine is using an cheap furnace filter instead of the provided sky screens.
Good enough for the girls I go with! 😉 -Al
Which, as I posted earlier, is what I did as an armourer. The important thing to add is getting your unit calibrated periodically. What is Oehler's frequency recommendation? ex. a time frequency like once every six months, or hrs of operation before calibration. This would be something those who use a Pro Chrono should follow too.
They state that accuracy is +/-.5% of measured velocity or better. For example, a 3000 fps load would be no more than 15 fps out. Say, 2993 to 3008 fps.
This is no different than getting a torque wrench or other precision device calibrated. For example, our torque wrenches were calibrated every six months.
Calibration ensures that what you are using remains accurate. Or, for the Campfire, and to be blunt, demonstrates how anal you are about accuracy.
![[Linked Image from i.imgur.com]](https://i.imgur.com/AP39Jhm.jpg)
