[shotgun1]

When running these calculations on the beartooth ballistics page, should we be entering anticipated expanded diameters of bullets after impact? For example; if I enter .308 for a 180g 30/06, the calculation for Thornily show it to be barely an adaquate deer load, but enter .450 as that bullet's diameter after impact and it's back to being an Elk load. What's the rule?

 

[Marshall Stanton]

Both of those calculations are based upon the bullets original nominal diameter... admittedly both are somewhat skewed towards the bigger bores. In any case, they are nothing more than a yardstick by which to compare one bullet/cartridge to another with a relative quantitative correlation.

I suppose that by inserting the anticipated expanded diameter of a given projectile you could also generate a useful comparison as well, however, you'd also have to calculate the impact velocity for it to have any relevance.

Hope this helps.

God Bless,

 

[DMC]

Marshall, would you be willing to post the math for Thornily? I don't have access to the internet at home, and sometimes would like to run a calculation.

DC

 

[Big Bore]

That's the problem with so many of these calculators. Energy says a .22-250 is more deadly than a .45-70, with the squaring of the velocity in the formula, fast will win every time. Thens there is momentum, better, but certainly not perfect; and these two, Taylor and Thronily, are geared toward solid non-expanding bullets. When you get into expanding bullets, man are you opening up another can of worms. Partition, rapid expanding, bonded core, X bullets...how can you come up with a formula to honestly compare bullets? Simple, you can't, not really. Now when it comes to shooting hard cast handgun bullets with relatively the same shape, I really like the Taylor formula. It is being uses as it is intended and does give you at least an idea of how one bullet stacks up against another.

 

[MikeG]

The expansion of the bullet and relationship between bullet expansion, wound channel, and decelleration is going to be a differential equation, rather than 'simple' math, which is probably why nobody tries to get that complicated. Hoped to leave those behind after college.... probably going to be difficult to work all of that into an Excel spreadsheet.

DMC, I think Marshall is moose hunting. If you don't hear from him in a week or so, try sending a PM. Probably will need 1 day to shoot a moose, and the rest of the week to cut it up.