paulvallandigham
Passed On
- Joined
- Jan 9, 2006
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The figures will vary depending on what you use for "Pi", but I ran this:
.50"(Diameter of the bore) divided by 2=.25
.25(Radius squared) x .25 =.625
.625 x Pi( 3.1416) = 1.9635
1.9635 x 11.5= 2.2580 Grains per cubic inch of bore.
Now, 31"( barrel length) x 2.2580 = 69.99 grains.(70 grains)
36"( barrel length) x 2.2580 = 81.288 grains( 81 grains)
I hope that helps you. :hatsoff:
Oh, you will be happy to know that I had my Brother, the Engineer, brush off the rust on my Mathematical "skills"(??? :rotf: ) to help me figure out how to do that formula a couple of years ago. I hope this detailed answer will help you and other members remember how to determine a volume(cube) of a certain cylinder. ( Pi R Squared ),where R(Radius) equals 1/2 the Diameter of the cylinder.
I made a chart for my own use, for all the popular calibers, in 2 inch( even numbered barrel lengths, for a quick reference table, from 28" to 44" barrel lengths. ( .32 to .75" calibers)
For uneven numbered barrel lengths, between those I have on my charts, I simply make a quick calculation of what 1/2 of the difference between the smaller and larger length is, and add that number to the small barrel length to answer questions. For barrels shorter than 28", I use the formula mentioned here and just run the calculations on my pocket calculator.
.50"(Diameter of the bore) divided by 2=.25
.25(Radius squared) x .25 =.625
.625 x Pi( 3.1416) = 1.9635
1.9635 x 11.5= 2.2580 Grains per cubic inch of bore.
Now, 31"( barrel length) x 2.2580 = 69.99 grains.(70 grains)
36"( barrel length) x 2.2580 = 81.288 grains( 81 grains)
I hope that helps you. :hatsoff:
Oh, you will be happy to know that I had my Brother, the Engineer, brush off the rust on my Mathematical "skills"(??? :rotf: ) to help me figure out how to do that formula a couple of years ago. I hope this detailed answer will help you and other members remember how to determine a volume(cube) of a certain cylinder. ( Pi R Squared ),where R(Radius) equals 1/2 the Diameter of the cylinder.
I made a chart for my own use, for all the popular calibers, in 2 inch( even numbered barrel lengths, for a quick reference table, from 28" to 44" barrel lengths. ( .32 to .75" calibers)
For uneven numbered barrel lengths, between those I have on my charts, I simply make a quick calculation of what 1/2 of the difference between the smaller and larger length is, and add that number to the small barrel length to answer questions. For barrels shorter than 28", I use the formula mentioned here and just run the calculations on my pocket calculator.