John Barness Ballistic Math

[Lars-K]

Don Miller wrote an article in Handloader regarding this rule.

Velocity increases at 1/4 the increase in case capacity.
Velocity increases at 1/4 the increase in bore area.
Velocity increases at 1/2 the reduction in bullet weight.

So, I have developed a online calculator using his algo.
Please read the info in the program before using!

Here is the link to the Calculator: http://www.weatherby.dk/Barsness.php
You can also see my other calculators by clicking the "software" link above the calculator.

Enjoy!

161199

[dtknowles]

Might be a cool tool but I bet the math does not hold at the extremes, like if you double the capacity of a 300 RUM I doubt you would get a 25 percent velocity increase or if you double the capacity of a .30 carbine I bet you would get more than a 25 percent velocity increase. These relationships are not linear.

Same deal on bullet weight a 110 grain bullet in a 30-06 does not go 50 percent faster than the 220 grain bullet Nosler data is 3450 vs. 2600 not 3900 vs. 2600 again not a linear relationship and they are not independent variables.

The computer simulation is probably not too bad in the middle range of the characteristics given the lack of sophistication of the models, the quarter and half relationships, why .25 instead of .234 or why .5 and not .43 or .57. How were the coefficients derived?

They are probably fun to play with.

Tim

[Mk42gunner]

It might not be perfect, but it is better than taking a WAG at a starting load for a new wildcat. I did a lot of comparing with this and Rocky Raab's similar case different bore, same bore similar case theory when I built a 6mm WSM about 2002. I still have all ten fingers and both eyes.

It also tends to blow holes in the "My improved '06 is better than a .300 Winchester" stories.

Robert

[Lars-K]

Well, the algo was not made by me, I just did the programming. And for me, (and Mk42gunner) it works as intended.

[JSnover]

It's as good a starting point as any and even Barnsness knew the vagaries of calculators, that's why he added the disclaimer at the bottom.
Thanks Lars.