One thing to keep in mind with radar 'guns' that the latest tech should fix is that there used to be a big variance in readings on older radar guns with projectiles that are changing velocity.
I used to work for a major league baseball team. We had our own radar gun, the latest and greatest at the time.
We supplied a feed to the Scoreboard to display during the game.
The scouts and others in the stands with radar guns complained loudly that our readings were too high, until we finally added software to adjust our speed readings that we showed to the public.
It was not an issue with our radar gun, it was a difference in technology.
Everyone else had older guns that could not pick up a base ball as quickly as ours, we were reading the ball out of the pitchers hand, the older guns did not get a lock as quickly and were reading a few MPH slower as the ball decelerated.
We did lots of testing with multiple calibrated guns to verify this.
Same reason you used to be able to 'beat' a cops radar if he opened up on you too far away.
Get a chirp on the detector, stand on the brakes and you could slow down the car before the gun could lock up.
Newer guns locked up faster so this would not work. Or better technique of ambushing prey at a closer distance.
Probably not relevant here, but I always found it interesting and many people think that a radar gun is a radar gun and they are infallible, and would all read the same.
Not the case.