Effective Kill Range Cartridge comparison formula. Finally combining SD Calibre and Energy all at once!

[Don_Parsons]

I hope we're not going to do the Army 1/2" Pine Board test are we.

Dang Namit,,, just when life was getting easy someone came along and changed all the rules. Ha.

https://youtu.be/OUM1r_444CY

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[shootsblanks]

Originally Posted by Nyksta

Just for reference, website info on Hornady Leverevolution 140gr FTX 357 magnum at 75 yards is 455 ftlbs

455ftlbs × .1007 bullet frontal area × .157 bullet sectional density = 7.19 kill power score.

That has more punch than a 223 Rem 55gr at 200 yards. (4.9 score).

So do the low scores associated to the 223 and 357 represent that a kill power score of 15 for deer is too high? Or are these low power shots stretching the limit with these cartridges? Are these shots making effective quick kills with one shot to the boiler room, or are they often requiring second shots to finish the job?

i think it indicates that deer are not that tough of an animal, and that while a 15 is great, it isn't mandatory. i have an american friend who hunts with a suppressed 300blk and shoots a 220gr subsonic soft cast hp through the slats, claims he doesn't lose deer and always has an exit wound on a broadside presentation within 100 yards. all that said, his load gives an EKR of 10.69 at 100 yards.
i believe that 357 with the correct bullet at a 7.19 would be fine. again, with the correct projectile.
one of the issues that a lot of these calculations have is that the right power level and the wrong bullet could be worse than under powered with the correct bullet, case in point, my dad and his 243 as mentioned above, even though he was using a properly constructed bullet, when used at close range it would struggle to reach the vitals while causing massive damage just under the hide.

[Nyksta]

Originally Posted by shootsblanks

i think it indicates that deer are not that tough of an animal, and that while a 15 is great, it isn't mandatory. i have an american friend who hunts with a suppressed 300blk and shoots a 220gr subsonic soft cast hp through the slats, claims he doesn't lose deer and always has an exit wound on a broadside presentation within 100 yards. all that said, his load gives an EKR of 10.69 at 100 yards.
i believe that 357 with the correct bullet at a 7.19 would be fine. again, with the correct projectile.
one of the issues that a lot of these calculations have is that the right power level and the wrong bullet could be worse than under powered with the correct bullet, case in point, my dad and his 243 as mentioned above, even though he was using a properly constructed bullet, when used at close range it would struggle to reach the vitals while causing massive damage just under the hide.

I think examples should not include a failed bullet due to explosion fragmentation, or failure to expand. The kill rating score could better be narrowed down to a more realistic number as long as the bullets function and give reliable one shot kill performance.

Irrelevant of what the deer number should be, the formula is useful for comparing the hitting power of one cartridge to another, as long as both bullets are functioning properly.

[marky_mark]

Originally Posted by sns2

I'm math illiterate. Somebody tell me how far away this formula says I can kill a moose with my 6.5 Squealmore and 125 Partitions.

If stinky is shooting than definitely inside 100 yards
Bring a box of shells too

[shootsblanks]

Originally Posted by Nyksta

I think examples should not include a failed bullet due to explosion fragmentation, or failure to expand. The kill rating score could better be narrowed down to a more realistic number as long as the bullets function and give reliable one shot kill performance.

Irrelevant of what the deer number should be, the formula is useful for comparing the hitting power of one cartridge to another, as long as both bullets are functioning properly.

i will give you that,
and it is still a more useful tool than ft-lbs for determining actual performance even when we disregard bullet construction

[Nyksta]

Originally Posted by marky_mark

If stinky is shooting than definitely inside 100 yards
Bring a box of shells too

I did the math on a 6.5 grendel with 123 gr eld bullets, and it actually has 21.9 kill power score at 100 yards. A proper shot to the vitals inside of 100 yards is reliable according to the formula and the 22.5 number for elk/moose. But hitting the vitals is the important part.

[vcmm]

Sooo . I'm going to take some 1/2" pine boards out to the pasture and I'm thinking,:00:fi ghting0007:

[JD848]

Originally Posted by marky_mark

If stinky is shooting than definitely inside 100 yards
Bring a box of shells too

Stinky did say he sat down with his sticks,which I think he should have never done due the heavy brush around him he said,i think if he would have stayed standing straight up for his first shot placement would have been much better,at least he got his moose and made know bones about how it went down.

So I got to give him credit for telling the way it went down instead of making it look like all was just perfect,human error which he never denied.i wonder how many guys on here did much worst and would never mention it to no one.

I could be wrong on the sitting part,but that's what I remember I think he wrote about his first shot,then he tried to reposition ,but his adrenaline was pumping buy the gallons,which he will learn from a very valuable hunt.He did say every thing was happening very fast after the first shot and when your on the edge things seem to happen much faster than some realize,but there really not it's just your gears grinding in your head.

Typing with only one eye for a few weeks,so if my grammar offends some ,it is what it is.

[Don_Parsons]

I agree,,, mid young SK did ok and the food is in the freezer.

One would only think that 734 more threads on cartridge stuff is yet to come, the new Creed 22,,, 6.8,,, 30,,, 338 are well underway along with many more coming down the pipe.

Yuppers,,, us humans could use more pine board in our lives since it makes life simple,,, looks like the predators are on the go now that the temps turned good this morning at -32c up here,,, lucky indeed.

Let's see,,, pack lunch,,, bring coffee,,, oh,,, and 2 hand fulls of ammo. Ha... One hates to run out of good times when things are going south.

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[WhiteTailAB]

Originally Posted by Nyksta

Dont worry Chuck, he wont take your place here on the forum

Where is the like button haha.

[Nyksta]

Originally Posted by chuck

Of course they exist. Their practical application as a reliable measure of killing power isn’t so quantifiable

Individually they are not complete for the killing power formula. Put them together and they do.
Multiply energy x sectional density x frontal area of a calibre = killing power score.

Killing power score shows just how much damage one situation will deliver compared to another calibre situation. Putting it in the vitals or into the non-vitals isnt a function on the calculator.

[Kurt505]

I killed a moose with less than 90/ftlbs of kinetic energy @ 90yds once.

[Salavee]

Originally Posted by chuck

Of course they exist. Their practical application as a reliable measure of killing power isn’t so quantifiable

Can you prove their existance ?

[Norwest Alta]

Originally Posted by Nyksta

I thought of asking that, but i realized i didnt care what the thoughts were considering how the other comments were so set on being troublesome.

Go check out the quality pack thread in hunting section. Constantly devaluing others views, but not really ever adding anything to the conversation.

I got to say I admire your willpower. He is a master baiter and dangles it out there that I bite everytime.

I do like your thread though.

[Lefty-Canuck]

Cabin fever is a horrible affliction

LC

[Pixel Shooter]

cleaned up, next time thread goes poof or people go poof, worst then teaching kids how to play in a sandbox

[Nyksta]

Back on tracks then,

My buddy who hunts a lot of coyotes uses a 22-250 with 55gr Vmax. He says that inside of 200 yards, shots to the lungs consistently have fast expiries, beyond 200 yards they tend to take longer.

Heres the info

.157 SD ×0.0394 calibre area ×957 ftlbs = kill power score of 5.9

Anyone have lots if coyote experience with the same or different calibre that can say there is a consistent distance that expiry times are noticeably longer.

[Nyksta]

Thinking about the effect bullet construction has on the differences with penetration. I think the standard score calculation would best be standardized for using traditional lead soft point bullets.

Most soft points have about 65% weight retention at their standard velocity ranges, bonded about 75%, and monometal bullets having near 100% weight retention. Barnes website estimates 28% more penetration distance, which I would say penetration is also directly determined by sectional density.

I would then say that as long as the velocities are within the proper expansion velocity range, that the calculation should increase the section density value using a bonded bullet by 15% (.65x1.15=.75), and for monometal 50% (.65x1.5=97.5)

[shootsblanks]

Originally Posted by Nyksta

Thinking about the effect bullet construction has on the differences with penetration. I think the standard score calculation would best be standardized for using traditional lead soft point bullets.

Most soft points have about 65% weight retention at their standard velocity ranges, bonded about 75%, and monometal bullets having near 100% weight retention. Barnes website estimates 28% more penetration distance, which I would say penetration is also directly determined by sectional density.

I would then say that as long as the velocities are within the proper expansion velocity range, that using a bonded bullet, the calculation should increase the section density value by 15% (.65x1.15=.75), and for monometal 50% (.65x1.5=97.5)

what kind of numbers would you estimate for those of us that use cast bullets that retain weight near 90% (sometimes 100% for the big bore hard cast shooters)?
shooting my 195gr flatnose (70/30 clip on/stick on acww alloy) through water jugs at 1700fps gave me a near perfect mushroom and retained 87% of its weight.
I understand that water is an imperfect medium and considered very hard on bullets, but it gives easy to reproduce results in a medium that everyone has easy access too. Nobody fails to calibrate water correctly, ballistics gel is another story.

[Nyksta]

Originally Posted by shootsblanks

what kind of numbers would you estimate for those of us that use cast bullets that retain weight near 90% (sometimes 100% for the big bore hard cast shooters)?
shooting my 195gr flatnose (70/30 clip on/stick on acww alloy) through water jugs at 1700fps gave me a near perfect mushroom and retained 87% of its weight.
I understand that water is an imperfect medium and considered very hard on bullets, but it gives easy to reproduce results in a medium that everyone has easy access too. Nobody fails to calibrate water correctly, ballistics gel is another story.

If the bullet is within its property velocity range for expansion, and you know what the retained weight is, then you could apply the multiplyer to your sectional density. This score is a comparison tool. So a person can have the standard as whatever they want, and the score can be whatever you want as well. Im starting to lean towards 10 to 12 as a deer kill power score.

If the bullet is so hard that it doesnt mushroom though, then the frontal area would be messed with. A 308 caliber bullet frontal area is 0.0745", but when it mushrooms to around .6" the frontal area now becomes 0.2827". Thats 3.7x more area now.

Im not sure how complicated this needs to get. If someone wants to compare similar performing bullets at similar velocities, then the score will reflect how they will compare. A 12 gauge slug vs a 308 has a huge huge score difference. Comparing different bullet performance is hard to figure out what the bullet changes in the equation.

[roper1]

Interesting read, OP, thanks!

[Nyksta]

On the discussion of similar style bullets and similar velocities, it is interesting to see how calibre size takes part in the required energy from the killing power formula, and how a higher ballistic coefficient carries the energy farther.

Heres some examples of the kill power score 22.5 for Elk.

308 Win 165gr Accubond, muzzle 2720 fps, needs 1217 ftlbs, max distance limit for elk energy at 460m.

308 Win 168gr Accubond Long Range, muzzle 2720 fps, needs 1193 ftlbs, max distance limit for elk energy at 560m.

270 Win 150gr Accubond, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 510m.

270 Win 150gr Accubond Long Range, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 580m.

6.5 Creedmoor 140gr Accubond, muzzle 2650 fps, needs 1433 ftlbs, max distance limit for elk energy at 280m.

6.5 Creedmoor 142gr Accubond Long Range, muzzle 2650 fps, needs 1413 ftlbs, max distance for elk energy at 360m.

[Kurt505]

Originally Posted by Nyksta

On the discussion of similar style bullets and similar velocities, it is interesting to see how calibre size takes part in the required energy from the killing power formula, and how a higher ballistic coefficient carries the energy farther.

Heres some examples of the kill power score 22.5 for Elk.

308 Win 165gr Accubond, muzzle 2720 fps, needs 1217 ftlbs, max distance limit for elk energy at 460m.

308 Win 168gr Accubond Long Range, muzzle 2720 fps, needs 1193 ftlbs, max distance limit for elk energy at 560m.

270 Win 150gr Accubond, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 510m.

270 Win 150gr Accubond Long Range, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 580m.

6.5 Creedmoor 140gr Accubond, muzzle 2650 fps, needs 1433 ftlbs, max distance limit for elk energy at 280m.

6.5 Creedmoor 142gr Accubond Long Range, muzzle 2650 fps, needs 1413 ftlbs, max distance for elk energy at 360m.

So what you’re saying is Stinky was right all along?

[propliner]

How is frontal area measured?

[Nyksta]

Originally Posted by propliner

How is frontal area measured?

Area of a circle calculator

https://www.google.com/search?q=area...obile&ie=UTF-8

[Salavee]

Originally Posted by propliner

How is frontal area measured?

pie r squared

[Thymallus arcticus]

If there are folks on this thread interested in delving deeper into the physics side of terminal performance, I would suggest having a read through these articles which are written as a bit of a critique of the various forms of performance quantification.

http://www.rathcoombe.net/sci-tech/b.../wounding.html

I am not a physicist so I can't say if I believe one authors thoughts over another, but I find the arguments presented in the above link interesting.

[propliner]

I just ran my .500 Jeffery numbers with a mild factory load.

A 535 grain round-nosed bullet has a kill power score at 100 yards of 306 or 13x what you'd need for elk.

At 400 yards it's a KPS of 166.

At 1000 yards it's a KPS of 64 but the drop is 55 feet.

[dave99]

Originally Posted by Nyksta

On the discussion of similar style bullets and similar velocities, it is interesting to see how calibre size takes part in the required energy from the killing power formula, and how a higher ballistic coefficient carries the energy farther.



Heres some examples of the kill power score 22.5 for Elk.



308 Win 165gr Accubond, muzzle 2720 fps, needs 1217 ftlbs, max distance limit for elk energy at 460m.



308 Win 168gr Accubond Long Range, muzzle 2720 fps, needs 1193 ftlbs, max distance limit for elk energy at 560m.



270 Win 150gr Accubond, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 510m.



270 Win 150gr Accubond Long Range, muzzle 2900 fps, needs 1324 ftlbs, max distance limit for elk energy at 580m.



6.5 Creedmoor 140gr Accubond, muzzle 2650 fps, needs 1433 ftlbs, max distance limit for elk energy at 280m.



6.5 Creedmoor 142gr Accubond Long Range, muzzle 2650 fps, needs 1413 ftlbs, max distance for elk energy at 360m.

I just ran the numbers for 6.5CM shooting 143gr ELDX at a zippy 2700fps (velocity from the Hornady website for their Precision Hunter load). Assuming a KPS of 15, I’m coming up with 935 ftlbs according to the formula listed by Hawks. Looking at my ballistics chart, that corresponds to approximately 800yds.

Assuming your elk KPS value of 22.5, this load requires 1403 ftlbs, which it retains to 460yds, according to my calculation. Much more than the anemic maximum distance that you calculated with the 6.5cm shooting 140gr Accubond.


Although I have never shot a big game animal past 430yds, my threshold for deer is a minimum impact velocity of 1800fps (2000fps for monos) and energy of 1000 ftlbs. With these parameters, the above 6.5CM load will max out at 720yds (this is where velocity drops below 1800fps) and 740yds (where kinetic energy drops below 1000 ftlbs).

Mandatory disclaimer: I’m not saying that I would shoot a deer at 700yds, as there is much more to it than the cold mathematics.




Sent from my iPhone using Tapatalk

[marky_mark]

Originally Posted by Kurt505

So what you’re saying is Stinky was right all along?

1400 Ft/lb with a 123gr out a Grendel is around 175 yards
If your taking that on a elk or moose hunt and leaving even a 308 at home your asking for trouble