Unfortunately, I could not find the data for my cast .36 cal balls. However, I did find the data for the Hornady 000 buckshot. First, I weighed 365 balls and sorted them into piles by variations of 0.1 grains. I found that they varied from 64.2 grains to 65.8 grains. The mean was 65.0 grains. The standard deviation was 0.2 grains. 11.28% of the balls weighed more than 1 standard deviation from the mean and 9.31% weighed less than one standard deviation from the mean.
Next, I measured the diameter of each of the 365 balls. The balls were all measured tangentially to the sprue. The mean diameter for the 365 balls was 0.351. The range was from .348 to .355. The standard deviation was 0.003
So, my conclusion was that there was not enough variation in the Hornady 000 buckshot balls to be a significant accuracy factor for the average, or even better shooter. Any accuracy variations from the common "wibbles and wobbles" will far outweigh any accuracy variation from the variations in Hornady 000 buckshot. Based on this study, I am of the opinion that Hornady 000 buckshot is "good medicine" for your .36 cal. rifle.
Has any of the forum members done an equivalent study on any other "store bought" .36 cal. balls? If so, what did you find?