BoydAllen
Gold $$ Contributor
Recently I had a chance to pick up a Harrell's Culver Classic powder measure in as new condition for a very good price.
I bought it because previous testing of this measure (this particular one) seemed to give more consistent throws than the the BR Premium that I have had for many years.
After spending some time finding the technique that this measure prefers so that its throws will stay inside of +-.1 gr. I set about finding out confirming what each of the six divisions between each number are worth in change of weight, in this case, of '05 133.
I set the measure with a milligram scale to throw 25 gr. (actually 24.96) and wrote down the setting. It was 45 2/3. Then I did the same thing to find the setting for 32 gr. (actually 32.04) which was an even 59. Subtracting one from the other gave a total difference in settings of 13 1/3. Multiplying 13 by six divisions and adding 2/6 gave an even 80 divisions for a weight change of 7 gr. Dividing 7 by 80 gave me the weigh change for each division as .0875 for this lot of this powder.
Carrying that a bit farther, I multiplied that times 6 to get the weight difference for a one number change, which is .525 gr., so one number change is worth a little over a half grain.
My next task will be to do a table that gives the closest settings for each .1 increase in charge weight from 24 to 32 grains. Once I have that I can set the measure from the chart, and use my smaller scale to verify and/or make a small adjustment to the measure to get the desired weight.
Realistically My work with this powder has been for a 6PPC, with a maximum charge span of 2 grains at most. Most of the time I am fine tuning a load and only making moves of perhaps .2 grain, so adjustments are pretty simple.
I bought it because previous testing of this measure (this particular one) seemed to give more consistent throws than the the BR Premium that I have had for many years.
After spending some time finding the technique that this measure prefers so that its throws will stay inside of +-.1 gr. I set about finding out confirming what each of the six divisions between each number are worth in change of weight, in this case, of '05 133.
I set the measure with a milligram scale to throw 25 gr. (actually 24.96) and wrote down the setting. It was 45 2/3. Then I did the same thing to find the setting for 32 gr. (actually 32.04) which was an even 59. Subtracting one from the other gave a total difference in settings of 13 1/3. Multiplying 13 by six divisions and adding 2/6 gave an even 80 divisions for a weight change of 7 gr. Dividing 7 by 80 gave me the weigh change for each division as .0875 for this lot of this powder.
Carrying that a bit farther, I multiplied that times 6 to get the weight difference for a one number change, which is .525 gr., so one number change is worth a little over a half grain.
My next task will be to do a table that gives the closest settings for each .1 increase in charge weight from 24 to 32 grains. Once I have that I can set the measure from the chart, and use my smaller scale to verify and/or make a small adjustment to the measure to get the desired weight.
Realistically My work with this powder has been for a 6PPC, with a maximum charge span of 2 grains at most. Most of the time I am fine tuning a load and only making moves of perhaps .2 grain, so adjustments are pretty simple.
