Lab radar is the best. If you can spend 8 grand on a gun, you can also buy Lab Radar.Really dumb question. Please don't take offense. Are you mixing the Nosler and Remington Brass? If so, that's a huge no-no and would explain everything.
Also, I am a huge fan of the LabRadar Chronograph. It's a whole new paradigm. Beg, buy, or borrow one to compare against your chrono. I note that your other chrono testing is on larger diameter bullets. Generally, I would say that it's normal to see this. Faster and smaller is harder to see for a lot of reasons. That's true of the LabRadar too, but if you get data, it's almost always good data which is not true of other chronographs. Another poster said, chronographs lie, paper doesn't. I would modify that to say that most chronographs lie, Labradar and paper don't. Anyway, try it.