Weighing powder charges to improve accuracy
6.4.5 THE ASTOUNDING POWDER MEASURE TEST! shows the standard deviation of 30 charges thrown with a Lyman 55 measure as .061 grain/IMR4227.
The standard deviation of 22 sets of 223 and 22-250 muzzle velocities of 40 and 53 grain bullets with 5.5 to 8.5 grains of Titegroup, is 13.3 fps.
Velocity/grain of the above is:
223, 40 gr bullet, 205.1 fps/3 gr powder, (205.1/3) X.061 gr = 4.2 fps = expected standard deviation.
223, 53 gr bullet, 172.1 fps/3 gr powder, (172.1/3) X .061 gr = 3.5 fps = expected standard deviation.
22-250, 40 gr bullet, 186.9 fps/3 gr powder, (186.9/3) X .061 gr = 3.8 fps = expected standard deviation.
22-250, 53 gr bullet, 171.6 fps/3 gr powder, (171.6/3) X .061 gr = 3.5 fps = expected standard deviation.
So, loading Titegroup with a Lyman 55 and shooting, the expected standard deviation of velocity, 3.5-4.2 fps; from powder charge variation alone is about a third of the actual measured standard deviation of velocity, 13.3 fps; which is caused by all the sources of variation; case weight and shooter ability and gun quality and case orientation and cartridge concentricity and bench rest equipment and neck tension and moon phase. Given the myriad descriptions of accuracy determinants, it seems unlikely to me, and Warren Page, that weighing powder charges has much effect on accuracy.