May I borrow your box?
To take this one step further, I got out my ballistic calculator spreadsheet and changed the muzzle velocity by 6fps to see how that changes the time of flight and therefore the point of impact at whatever distance I was shooting. That gave me a pretty good? estimate of how much better groups I'd get by reducing errors in powder weight from .1 grains all the way to zero. My calculator says for a bullet with a G1 BC of .500, a muzzle velocity of 3100fps, an increase of 6fps changes the 1000yd time of flight from 1.383s to 1.380s and that reduces drop at 1000 yds by 1.6". At 500yds, it is .55308s vs .55194s and that wil changes drop by .24". Your mileage may vary.