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DC

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DC

But the Taylor knok out value is a very good cartridge comparison formula.

bullet dia. X bullet weight X muzzle velocity / 7000 gns.

.458 x 465 X 2300 fps / 7000 =69.975

this is a way to compare different cartridges that you know will work, to compare against cartridges you want to see if they will work.

Hope this helps,

Halfbreed

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DC

Hi DMC,DMC said:

DC

I was cruising over the old posts and I saw your question. I am curious also as to what the Thorniley formula is. I have ran some numbers through it and the formula appears to be the following.

=2.866*velocity[fps]*(bullet weight[grains]/7000)*SquareRoot(bullet diameter[in])

The square root of the bullet diameter explains why the Thorniley stopping power value does not weigh diameter as heavily as the Taylor formula does.

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I give you another factor formula that I have developed, for you to play with, based on some things we have learned along the way. The others are based on a non-expanding bullet.....mine works both ways:

Maplat Area X Sectional Density X Velocity = Power Factor

Try it out!.........James

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James,James Gates said:

I give you another factor formula that I have developed, for you to play with, based on some things we have learned along the way. The others are based on a non-expanding bullet.....mine works both ways:

Maplat Area X Sectional Density X Velocity = Power Factor

Try it out!.........James

Haven't tried your formula yet, but it's interesting. What about bullets that have a very small Maplat area, e.g. pointed bullets? Since you are including Maplat area in your formula, does this imply that you're a hard-cast guy?

Brian

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Since I first started playing with a comparison factor, I realized that Sectional Density should replace Weight.

Sectional Density X Meplat Area x Velocity = Factor.

This factor formula takes into consideration the expanded MA where the others do not.

When you are playing with Peter Thornily formula, etc.....remember that are for non-expanding solids!

The only problem is recovering expanded jacked bullets to measure the MA.....but it can be done with a little work and water soaked paper situated at various ranges. Here we really see the diference in velocity and MA on jacketed bullets at various ranges.

I have never been satisfied that the ft/lbs of energy was a real yardstick for comparing Lethal Potential of various loads. At best it is a potential. Bullet design governs MA.

Regards, James

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Here's one that can be used to compare one bulet load to another!

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A non-expanding bullet with a large Meplat Area does not lose SD.

Regards, James

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How much does it expand? A bullet that expands to 2X its diameter winds up with a pretty anemic SD of 1/4 the SD of the same bullet that doesn't expand.

What medium will cause expansion? I have some bullets that are so stout that they will expand only in a very dense medium - flesh won't do it.

How much weight will the bullet shed on its trip? Jacket seperation, lead pieces breaking off, etc.

How quickly - at what depth - is expansion achieved?

Personally, I prefer a flat-nose, non-expanding bullet for

DC

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In calibers below .357" .....such as my .30-06....I go with a jacketed bullet that has proven performance in game.

Just some thoughts....James

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