Unlisted Powders in Load All Chart
Posted by on 01 November 2011 02:34 PM
There are many new powders on the market that are not yet listed on the bushing chart of the Load All. Using these directions, one can determine the proper bushing to use for these newer powders.|
It is first necessary to establish a base line. This is done by dropping the powder of your choice in any bushing and weighing the charge. Divide the test bushing number by the weight in grains that was dropped from it. This gives you the MVD (Measured Volume Density) for the new powder.
Then, multiply the MVD number times the desired charge for that powder. The result is the bushing number you should use. All bushings have molded numbers. Be sure to use the leading decimal in your calculation. Since the result may not come out perfectly, use the next smaller bushing size. Always confirm the charge before loading when calculating the capacity.
Below is the math formula for this calculation.
Test bushing number
------------------------------- = MVD
Weight of that charge
MVD x Desired charge of new powder = Correct bushing size.
The MVD number is not to be confused with the VMD numbers commonly used in many of our powder measuring tools. Do not use a VMD (Volume Measure Density) number that you find in any of our literature for the purposes of this specific calculation as it would create a dangerous condition.