Hunting Ammo Killing Power

[meketrefe]

Before the hunting season how do you measure the killing potential of a round?

Do you match bullets to animal type and body weight or simply make a more or less educated guess?

We could talk for days about terminal design and specific properties in any single use including hand
gun usage but for the sake of simplicity and to see if we can answer some very fundamental questions
lets see if we can define a set of rules to assist with this process.

I keep a log of my shooting including hunts and also follow a few hunting forums to discuss some of
these but at the same time I see in other forums how people are following a completely different
set of directives so I wonder what other factors could be at play here.

My approach might seem pretty simplistic but I try to make sure we use some of the tools and knowledge base that
is already there. In some ways this should not be different than cheeking values when reloading. Of course there is no substitute for carefully studying the bullets and the game animals one is targeting, practicing with that ammo for external ballistics and accuracy and ultimately knowing when to say no to make sure we don't hurt an animal unnecessarily.

When researching killing potential and in order to assure fast killing I move with a very simple set
of parameters:

A) Placement

B) Wounding Potential

C) Shock / CNS disruption

There is a strict relationship between these three dimensions that impact terminal performance.

In addition, and in order to determine the potential of a given projectile, I look at the animal type, the type of bullet and try to match the bullet to the body weight and animal type.

I consider five attributes to play a fundamental role in order to determine the killing potential
and speed of killing a round might have:

1) Caliber / Frontal section

2) Weight of the bullet

3) Speed at the target

4) The above determine sectional density and momentum

5) Finally and very important, terminal design / bullet construction


Then by using tracking tables and/or popular software I will determine what type of value I need at the estimated hunting distances for the intended game and heaviest possible weight.

I have been trying to devise a simple formula that can be corroborated wiht another tool like the HITS index from hornady.

HITS calculator - Hornady Manufacturing, Inc

In addition provide a quick visual determination of a value index based
on those parameters.

What about something like this chart style where you can see the value distribution
being the red the compounding killing factor?

1000 is big game hunting... I called it KOI as killing index or KO index.

Lets do the 223 Remington with 77gr tmk.

KOI Between 1000-800 is mid game..

Below 800 is small game. We have plenty of speed and momentum. While 77gr hpbt is broad wounding might not be the best choice considering we don't get to medium weight for lets say deer and also
short on penetration with this type of bullet. Solids compensate for lower SD at higher speeds so
I need to find a way to reflect that in the index.

But initial is this a good way to visually measure killing potential or you think it is too elaborate?
Perhaps ranking in each category with a simple value like 1 to 4 and then aggregate this way.

Any feedback, thoughts, recommendations are greatly appreciated.

 

[Marine Cpl]

Most guys can't even research their carry ammo and end up carrying ammo that performs no better if not worse than a FMJ through the their short 3 inch barrels.

I doubt that they research their hunting rounds.

They'll go to the gun store and say to the clerk, "You got any 30.06 left?" That is about as much research as they'll do.

Then you have the ones who pick the highest grain not taking velocity into account.

 

[meketrefe]

Most guys can't even research their carry ammo and end up carrying ammo that performs no better if not worse than a FMJ through the their short 3 inch barrels.

I doubt that they research their hunting rounds.

They'll go to the gun store and say to the clerk, "You got any 30.06 left?" That is about as much research as they'll do.

Then you have the ones who pick the highest grain not taking velocity into account.

You might be right some people might do that but others might do some research. We will see.

Velocity upon impact is a huge factor. In fact in small calibers determines both proper energy levels but also proper activation
of the projectiles that in many cases we underestimate. many manufactures are also a tad optimistic and values do not reflect
what the bullets actually do in the field. When in doubt, simply inject more speed. Speed is what gets the job done many times,
plus flatter trajectories and more forgiving on the human aiming error or estimation.

We should all stop talking about energy and speed and the muzzle. That is so irrelevant. I mean, it gives you some idea but
in reality what it matters is what the bullet is doing down range.

 

[dsdmmat]

Aren't you just calculating energy levels with this? Only with a more complicated and arbratrary value assigned to catagory of animal?

200 grain bullet striking at 2113 FPS = 1983 FT LBS of energy.


It is easy to understand.

 

[Magnus]

Who knew all those physics classes would pay off some day. Lol.

 

[meketrefe]

Aren't you just calculating energy levels with this? Only with a more complicated and arbratrary value assigned to catagory of animal?

I don't use energy but momentum that what really matters. Also known as power factor in IDPA and other places.
In order to be accurate one needs to use the frontal section, weight, sectional density and speed too.
As frontal section increases then SD might decrease but then that is compensated with weight or find a balance
in between.
In general terms a rifle bullet should do well in at least 3 areas otherwise terminal performance is impacted.

I don't think there is anything arbitrary in the HITS formula or my method. The only tricky part is how to reflect some
factors like solid bullets moving at high speed might be more effective than the same bullet in heavier grain at slower
speed just because of the construction so the speed yields the best results.
The smaller the caliber the better we do with speed given decent sd and weight and also the bullet stays together
if that is intended. Unlike varmints where explosive nature might be desired.

And then have an easier way to rate and visualize performance. Some of these exceptions might be better handled
going through a rating and keep that up to date.

One thing is clear. The typical speeds and energy values alone do not tell much about killing potential, specially
values at the muzzle.

What do you think about the HITS index? IMO there should be a way to roll up the bullet construction into the factor.

 

[meketrefe]

Who knew all those physics classes would pay off some day. Lol.

There are some physics but I see this one more like group and relate. Tables and compounding type of work.
Obviously one need to have information about the specific thresholds and grouping criteria.

 

[ECU Pirates]

I can't think of anyway to account for bullet construction.

 

[ECU Pirates]

Most guys can't even research their carry ammo and end up carrying ammo that performs no better if not worse than a FMJ through the their short 3 inch barrels.

I doubt that they research their hunting rounds.

They'll go to the gun store and say to the clerk, "You got any 30.06 left?" That is about as much research as they'll do.

Then you have the ones who pick the highest grain not taking velocity into account.

We don't all have spare frying pans to shoot sir. That being said the "any 30.06 left would most likely be core-lokt and it kills just fine!

 

[dsdmmat]

I don't use energy but momentum that what really matters. Also known as power factor in IDPA and other places.
In order to be accurate one needs to use the frontal section, weight, sectional density and speed too.
As frontal section increases then SD might decrease but then that is compensated with weight or find a balance
in between.
In general terms a rifle bullet should do well in at least 3 areas otherwise terminal performance is impacted.

I don't think there is anything arbitrary in the HITS formula or my method. The only tricky part is how to reflect some
factors like solid bullets moving at high speed might be more effective than the same bullet in heavier grain at slower
speed just because of the construction so the speed yields the best results.
The smaller the caliber the better we do with speed given decent sd and weight and also the bullet stays together
if that is intended. Unlike varmints where explosive nature might be desired.

And then have an easier way to rate and visualize performance. Some of these exceptions might be better handled
going through a rating and keep that up to date.

One thing is clear. The typical speeds and energy values alone do not tell much about killing potential, specially
values at the muzzle.

What do you think about the HITS index? IMO there should be a way to roll up the bullet construction into the factor.

using muzzle velocity, weight and BC you can figure out what your bullet is going to hit with at distance, do the energy calculation with those numbers and you will know how it will perform.

I don't know what formulas the hits index is using, it won't show it. How did they come up with the # for animal? In Germany the hunting regulations told you how much energy your round had to have depending on the animal. It was an easy calculation. You just plug in the numbers and if it made it you were good. Just like the IPSC power factor, weight times velocity /1000.

Seems to me Hornady put thier own spin On things that have been talked about for a while. The two articles below are old news but worthy of a look. I look at the hits calculator as a new knob on a sports car. Nobody knows how it works or why they need it but they just had to have it.


I do not worry about such things anyway. The only things I shoot on a normal basis doesn't care about energy. The only living things I will be shooting I Wont be worring if it suffers before it dies.

KILLING POWER
The Myth of Minimum Impact Energy

 

[ECU Pirates]

The 35 gunner has a taylor ko score of 21.

The .223 77gr listed here has a score of 6.

Not sure how this calculation differs from the taylor but the scores are interesting for both.

 

[spat]

What you are actually talking about is energy delivered to vital tissue.

All the other factors are just about optimizing that.

Bullet construction (expansion and sectional density) are about making sure the energy ends up in vital tissue instead of dissipating in non vital tissue, or passing right through it.

Momentum is another attempt to compensate for the energy that will be lost in the non-vital tissue covering the "important stuff".

As long as you assume that the bullet remains intact, and delivers the energy quickly, that is what you are actually trying to measure.

 

[meketrefe]

Round A can have more energy than round B yet less momentum.
We understand this and what it means when two objects impact right?
For example, that is why power factor (like to make major in IDPA) was introduced.

 

[meketrefe]

The 35 gunner has a taylor ko score of 21.

The .223 77gr listed here has a score of 6.

Not sure how this calculation differs from the taylor but the scores are interesting for both.

The taylor is good but still does not account for some variables I want to reflect like hardness, construction.
Pherhaps we should make it easy and simply create a score value based on the design/behaviour in the animal is intended for.
for example if you shoot a deer with a varmint grenade the score in the table will be very low because you will have
a broad wound but hardly any penetration. In this case the speed that is great for a PD is really bad for anything else.

 

[meketrefe]

It is getting late today but let me put an example and see what you guys think? ...

Scenario A - I take a shot at white tail at 200 yards with a 308W hornaday 150gr spbt like interlock. Very decent bullet.
Scenario B- I take the same shot at white tail at 200 yards with a 308W 180gr Barnes TSX. heavy bad ass bullet.

Which one kills the deer better and/or faster and why?

 

[Marine Cpl]

It is getting late today but let me put an example and see what you guys think? ...

Scenario A - I take a shot at white tail at 200 yards with a 308W hornaday 150gr spbt like interlock. Very decent bullet.
Scenario B- I take the same shot at white tail at 200 yards with a 308W 180gr Barnes TSX. heavy bad ass bullet.

Which one kills the deer better and/or faster and why?

If they both have complete pass through on the deer, I would think the lighter bullet would be better due to the faster velocity.

More velocity equals a larger stretch cavity that'll tear further creating a bigger wound.

 

[Acer-m14]

when i started reloading for my .270win , the book shows loads for 2800fps to like 3100* ..
the note for the * at the bottom of the page is * best hunting load ... but no other information ...

so i'm like scratching my whiskers and thinking .. 2900fps seem good ... speed n weight ballistic data shows ftlb energy at 150 yards is nice for a deer if not overkill hehehe ... range shooting ... 1 inch groups at 100 yrds .. which is awesome for me .. I flinch like a you goosed a jackrabbit .. LOL ..

why should i beat my shoulder like its a 30-06 when the data is enough at 2900 ....

308W hornaday 150gr spbt .. faster .. more internal shock

 

[MilesTeg]

Let me wart by saying I get why your doing this. I think it's a good thing to put technical information out there in a simplistic manner. From the screen shots you have presented I think you have done just that.

I get your conundrum. Bullet construction should be factored in there. The only idea I have for that is a table of bullets to pull values from. Maybe the pulled value would be the manufacturers impact speed range. Use the mean speed for the optimum value and as you deviate from the mean the value goes down. Then setup once you cross the speed thresholds the number falls off. Low it would function like a ball round high it would function like a varmint round. I don't know how to determine a value for these conditions that would work.

I would like to add some talk about the whole idea it's self. It looks like your designing this as an app. I think this is the perfect way to get this out to the public. Your format appears to be easy enough for people to use. If you charge a minimal amount I think you will have a good side income. If you charge too much I don't see you getting much sales and I will lay out why next.

OK here's a few criticisms and improvement ideas. First I'm not 100% who would be using this. The reason I ask this is because most fudds don't have a clue what their speed on target is going to be. Like you stated earlier everyone is hung up on muzzle velocity. So my thought is if someone is versed well enough with ballistics and can not only understand their velocity on target but to calculate it then this sort of simplistic app. This is where the suggested improvements come in. First one is made make a drop down menu with common commercial hunting bullets and neglect the reloaders. Then add use estimated range to target instead of velocity. Use the manufacturers data to calculate the impact velocity. You could also tie in the bullet design impact speed as described above.

Next I would add an advance button or tab. This would be geared towards the reloaders or people who know how to get their velocity on target. Or you can give the optional calculations of with; muzzle velocity, BC, sectional density or bullet drop down menu, range to target. There was something else I wanted to add to the advance tab but lost it sorry the downfall of typing on the phone.

Please don't take this as me downing the idea I'm genuinely trying to help.

 

[spat]

Let me wart by saying I get why your doing this. I think it's a good thing to put technical information out there in a simplistic manner. From the screen shots you have presented I think you have done just that.

I get your conundrum. Bullet construction should be factored in there. The only idea I have for that is a table of bullets to pull values from. Maybe the pulled value would be the manufacturers impact speed range. Use the mean speed for the optimum value and as you deviate from the mean the value goes down. Then setup once you cross the speed thresholds the number falls off. Low it would function like a ball round high it would function like a varmint round. I don't know how to determine a value for these conditions that would work.

I would like to add some talk about the whole idea it's self. It looks like your designing this as an app. I think this is the perfect way to get this out to the public. Your format appears to be easy enough for people to use. If you charge a minimal amount I think you will have a good side income. If you charge too much I don't see you getting much sales and I will lay out why next.

OK here's a few criticisms and improvement ideas. First I'm not 100% who would be using this. The reason I ask this is because most fudds don't have a clue what their speed on target is going to be. Like you stated earlier everyone is hung up on muzzle velocity. So my thought is if someone is versed well enough with ballistics and can not only understand their velocity on target but to calculate it then this sort of simplistic app. This is where the suggested improvements come in. First one is made make a drop down menu with common commercial hunting bullets and neglect the reloaders. Then add use estimated range to target instead of velocity. Use the manufacturers data to calculate the impact velocity. You could also tie in the bullet design impact speed as described above.

Next I would add an advance button or tab. This would be geared towards the reloaders or people who know how to get their velocity on target. Or you can give the optional calculations of with; muzzle velocity, BC, sectional density or bullet drop down menu, range to target. There was something else I wanted to add to the advance tab but lost it sorry the downfall of typing on the phone.

Please don't take this as me downing the idea I'm genuinely trying to help.

If you want a good empirical measure, you should create a setup that will actually measure energy deposited into gelatine or something.

Maybe you setup a 6" block of gel with a chrono on either side (obviously would take some work to make practical), then you set that behind a 12" block of gel. you can take the velocity lost in the 6" piece and the Bullet weight to calculate the effective delivered energy.

For large game, maybe the first block should be thicker, or should have a hard covering or something. Make it work like rockwell hardness scales for metal with A for varmint loads with a 3" front block, B for medium w/ a 8 inch block and C for large game with a 18" front block and a 12" measuring block or something like that. The scale could be something simple like ft lbs deposited in the measuring block or something.

 

[MilesTeg]

The problem with doing testing like that is that it's expensive and time consuming. This could be a full time in itself. Another aspect would have to be sample size it would be difficult to surpass what the manufacturers have already done. Also it's hard to verify by an outsider. That's why I thought the manufacturers published bullet speeds would be the way to go.

The test you have laid out is an interesting one. I would like to see one done and see the results. If I had the ability I would love to get some ballistics gel and mess around.

 

[meketrefe]

If they both have complete pass through on the deer, I would think the lighter bullet would be better due to the faster velocity.

More velocity equals a larger stretch cavity that'll tear further creating a bigger wound.

Ok. lets say the 150gr is a reduced load so impact speeds are the same.

 

[meketrefe]

when i started reloading for my .270win , the book shows loads for 2800fps to like 3100* ..
the note for the * at the bottom of the page is * best hunting load ... but no other information ...

so i'm like scratching my whiskers and thinking .. 2900fps seem good ... speed n weight ballistic data shows ftlb energy at 150 yards is nice for a deer if not overkill hehehe ... range shooting ... 1 inch groups at 100 yrds .. which is awesome for me .. I flinch like a you goosed a jackrabbit .. LOL ..

why should i beat my shoulder like its a 30-06 when the data is enough at 2900 ....

308W hornaday 150gr spbt .. faster .. more internal shock

No need to bother with speeds.
One should get very good speeds at the ranges one normally shoots and I think in this case the bullet and speed are more than adequate
so +/- speeds at those ranges knowing your projected poi and good placement is not going to make any difference.

for the 150gr spbt lets assume it is a reduce load and it strikes at the same speed as the mighty 180gr TSX.

 

[spat]

The problem with doing testing like that is that it's expensive and time consuming. This could be a full time in itself. Another aspect would have to be sample size it would be difficult to surpass what the manufacturers have already done. Also it's hard to verify by an outsider. That's why I thought the manufacturers published bullet speeds would be the way to go.

The test you have laid out is an interesting one. I would like to see one done and see the results. If I had the ability I would love to get some ballistics gel and mess around.

For sure it's not a garage project as anything more than a proof of concept. To be useful it would need to be developed into a strict testing regime and then manufacturers could certify their rounds to it.

I would say you could do a proof of concept with less than a hundred rounds though, but for a hobby that would still be a major undertaking.

"our new BA723 round will deliver 250ftlbs in the spat "B" test. sort of thing.

 

[meketrefe]

......

Please don't take this as me downing the idea I'm genuinely trying to help.

Any ideas or critizism I take as a blessing so many thanks for sharing your thoughts with me.
We should all be like babies that are open to absorbe everything and this way continue to grow.
I like the app idea but I think that is an evolution from first getting a simple yet reliable formula.
I think a ranking table for every bullet might work and from there factor that with the other variables
don't you think?

 

[Greywolf224]

@meketrefe God bless you. My rule of thumb for hunting is if it fits the chamber...I shoot it. The only time I ever not retrieved my game is if I totally missed the animal.
Obviously I will not hunt big game with a .22.

 

[meketrefe]

For sure it's not a garage project as anything more than a proof of concept.
"our new BA723 round will deliver 250ftlbs in the spat "B" test. sort of thing.

I like the idea of testing at least some limited yet meaningful testing. Specially with new bullets that come out or
to test the capability of a given bullet intended for one use to see how it works but this will be limited due to time
and budget.
Also I think there is enough forensic information to create a meaningful ranking criteria for most bullets in the market
if not all. This could start with the well known bullets and also a rough estimate that will be refined as we move
forward.

Your thoughts?

 

[meketrefe]

@meketrefe God bless you. My rule of thumb for hunting is if it fits the chamber...I shoot it. The only time I ever not retrieved my game is if I totally missed the animal.
Obviously I will not hunt big game with a .22.

I think this might not be critical for a lot of people if one sticks to what is known to work and for the average white tail hunter
but at the same time I think there are a lot of people that are being short handed due to trusting arbitrary criteria, inflated ballistics
data and even using the wrong projectiles for the job at hand.

The 22LR is a great all around varmint round. In an emergency/shtf situation we could try to use it for more but we are not going to
suggest poaching or any other crazy criteria that normally is both unethical and illegal in most places.

 

[Marine Cpl]

Ok. lets say the 150gr is a reduced load so impact speeds are the same.

If they are the same speeds than the heavier will penetrate further.

If they both however have complete pass through on the deer which I would imagine so then it doesn't really matter. The next factor you'd have to consider is expansion size.

 

[ManrisFrack]

If they are the same speeds than the heavier will penetrate further.

If they both however have complete pass through on the deer which I would imagine so then it doesn't really matter. The next factor you'd have to consider is expansion size.

The particulars of expansion matter too. The cup and core 150gr will fragment to some degree depending on impact location. Odds are high that a significant portion of the bullet's mass fails to fully penetrate. The TSX will plow through anything on a whitetail and lose very little, if any, mass.

I admire what you're trying to do and wish you luck, but it may be that terminal ballistics is affected by too many variables to distill.

For those looking for a really good 'backyard' bullet study, I'll point you here. I know meketrefe has seen it (Xman's work) and it is 6.8 focused, but it has really given me a ton of insight. He goes into great detail about his setup and methods.

 

[Marine Cpl]

The particulars of expansion matter too. The cup and core 150gr will fragment to some degree depending on impact location. Odds are high that a significant portion of the bullet's mass fails to fully penetrate. The TSX will plow through anything on a whitetail and lose very little, if any, mass.

I admire what you're trying to do and wish you luck, but it may be that terminal ballistics is affected by too many variables to distill.

For those looking for a really good 'backyard' bullet study, I'll point you here. I know meketrefe has seen it (Xman's work) and it is 6.8 focused, but it has really given me a ton of insight. He goes into great detail about his setup and methods.

Yep. I think the TSX is the best rifle bullet created. It expands to double it's size and doesn't shed weight by fragmenting insuring maximum penetration.

Who wants fragments in their meat?