They are very handy for working up loads. On my pact pro xp, one of my sensors got moved an inch in on the rail. That meant all my readings were reading 200 feet high. Once I figured it out, I moved it back to the spot the sensor was supposed to be and velocities were back where they were supposed to be. Was kinda bummed, I was pretty happy with 3k from the 127lrx out of the CM and a 22" barrel.
