7mm Rem Mag elk rifle

[Woodrow F Call]

How does a bullet expand without the energy to do so?

You are misunderstanding my point. Maybe rewording will help.

A number for Kinetic Energy does not indicate how much better one bullet will kill over another.

I was not saying that Energy is not needed for a bullet to kill. That idea is nonsensical.

 

[backcountry_hunter]

4. Presumption of "Kinetic Energy Deposit" to Be a Mechanism of Wounding:​

Serious misunderstanding has been generated by looking upon "kinetic energy transfer" from projectile to tissue as a mechanism of injury. In spite of data to the contrary (1, 63), many assume that the amount of "kinetic energy deposit" in the body by a projectile is a measure of damage (2-5, 36, 37, 40). Such opinions ignore the direct interaction of projectile and tissue that is the crux of wound ballistics. Wounds that result in a given amount of "kinetic energy deposit" may differ widely. The nondeforming rifle bullet of the AK-74 (Fig 6) causes a large temporary cavity which can cause marked disruption in some tissue (liver), but has far less effect in others (muscle, lung, bowel wall) (9). A similar temporary cavity such as that produced by the M-16 (Fig 2), stretching tissue that has been riddled by bullet fragments, causes a much larger permanent cavity by detaching tissue segments between the fragment paths. Thus projectile fragmentation can turn the energy used in temporary cavitation into a truly destructive force because it is focused on areas weakened by fragment paths rather than being absorbed evenly by the tissue mass. The synergy between projectile fragmentation and cavitation can greatly increase the damage done by a given amount of kinetic energy.
A large slow projectile (Fig 7) will crush (permanent cavity) a large amount of tissue, whereas a small fast missile with the same kinetic energy (Fig 4) will stretch more tissue (temporary cavity) but crush little. If the tissue crushed by a projectile includes the wall of the aorta, far more damaging consequences are likely to result than if this same projectile "deposits" the same amount of energy beside this vessel.

Many body tissues (muscle, skin, bowel wall, lung) are soft and flexible--the physical characteristics of a good shock absorber. Drop a raw egg onto a cement floor from a height of 2 m; then drop a rubber ball of the same mass from the same height. The kinetic energy exchange in both dropped objects was the same at the moment of impact. Compare the difference in effect; the egg breaks while the ball rebounds undamaged. Most living animal soft tissue has a consistency much closer to that of the rubber ball than to that of the brittle egg shell. This simple experiment demonstrates the fallacy in the common assumption that all kinetic energy "deposited" in the body does damage.

The assumption that "kinetic energy deposit" is directly proportional to damage done to tissues also fails to recognize the components of the projectile-tissue collision that use energy but do not cause tissue disruption. They are 1) sonic pressure wave, 2) heating of the tissue, 3) heating of the projectile, 4) deformation of the projectile, and 5) motion imparted to the tissue (gelatin bloc displacement for example).

The popular format for determination of "kinetic energy deposit" uses a chronograph to determine striking velocity and another to determine exit velocity. A 15-cm thick block of tissue simulant (gelatin or soap) is the target most often used. This method has one big factor in its favor; it is simple and easy to do. As for its validity, the interested reader is referred to wound profiles shown in Figs 1-7. Comparing only the first 15 cm of the missile path with the entire missile path as shown on the profiles shows the severe limitation of the 15-cm block format. The assumption by weapons developers that only the first 15 cm of the penetrating projectile's path through tissue is of clinical significance (64) may simplify their job, but fails to provide sufficient information for valid prediction of the projectile's wounding potential. The length of bullet trajectories through the human torso can be up to four times as long as those in these small blocs. Even if this method were scientifically valid, its use has been further flawed by nearly all investigators who have included the M-16 rifle bullet in those projectiles tested. This method assumes that the projectile's mass remains constant through both chronographs. The M-16 routinely loses one third of its mass in the form of fragments which may remain in the target (see Fig 2). The part of the bullet that passes through the second chronograph screens weighs only about two-thirds as much as the intact bullet that passed through the first set of screens. No provision is made for catching and weighing the projectile to correct for bullet fragmentation when it occurs. The failure to correct for loss of bullet mass can cause large errors in "energy deposit" data (8).

Surgeons sometimes excise tissue from experimental missile wounds that is, in their judgment, nonviable and compare the weight of tissue excised with the "kinetic energy deposited" (65). A surgeon's judgment and his technique of tissue excision is very subjective, as shown by Berlin et al (66), who found in a comparison that "One surgeon excised less tissue at low energy transfers and rather more at high energy transfers than the other surgeon, although both surgeons used the same criteria when judging the tissues." None of these experiments included control animals to verify that tissue the surgeon had declared "nonviable" actually became necrotic if left in place. Interestingly, all studies in which animals were kept alive for objective observations of wound healing report less lasting tissue damage than estimated from observation of the wound in the first few hours after it was inflicted (43-47, 67, 68). In a study of over 4,000 wounded in WW II it was remarked, "It is surprising to see how much apparently nonvital tissue recovered" (69).

Anyone yet unconvinced of the fallacy in using kinetic energy alone to measure wounding capacity might wish to consider the example of a modern broadhead hunting arrow. It is used to kill all species of big game, yet its striking energy is only about 50 ft-lb (68 Joules)-- less than that of the .22 Short bullet. Energy is used efficiently by the sharp blade of the broadhead arrow. Cutting tissue is far more efficient than crushing it, and crushing it is far more efficient than tearing it apart by stretch (as in temporary cavitation).

 

[Vandy321]

4. Presumption of "Kinetic Energy Deposit" to Be a Mechanism of Wounding:​

Serious misunderstanding has been generated by looking upon "kinetic energy transfer" from projectile to tissue as a mechanism of injury. In spite of data to the contrary (1, 63), many assume that the amount of "kinetic energy deposit" in the body by a projectile is a measure of damage (2-5, 36, 37, 40). Such opinions ignore the direct interaction of projectile and tissue that is the crux of wound ballistics. Wounds that result in a given amount of "kinetic energy deposit" may differ widely. The nondeforming rifle bullet of the AK-74 (Fig 6) causes a large temporary cavity which can cause marked disruption in some tissue (liver), but has far less effect in others (muscle, lung, bowel wall) (9). A similar temporary cavity such as that produced by the M-16 (Fig 2), stretching tissue that has been riddled by bullet fragments, causes a much larger permanent cavity by detaching tissue segments between the fragment paths. Thus projectile fragmentation can turn the energy used in temporary cavitation into a truly destructive force because it is focused on areas weakened by fragment paths rather than being absorbed evenly by the tissue mass. The synergy between projectile fragmentation and cavitation can greatly increase the damage done by a given amount of kinetic energy.
A large slow projectile (Fig 7) will crush (permanent cavity) a large amount of tissue, whereas a small fast missile with the same kinetic energy (Fig 4) will stretch more tissue (temporary cavity) but crush little. If the tissue crushed by a projectile includes the wall of the aorta, far more damaging consequences are likely to result than if this same projectile "deposits" the same amount of energy beside this vessel.

Many body tissues (muscle, skin, bowel wall, lung) are soft and flexible--the physical characteristics of a good shock absorber. Drop a raw egg onto a cement floor from a height of 2 m; then drop a rubber ball of the same mass from the same height. The kinetic energy exchange in both dropped objects was the same at the moment of impact. Compare the difference in effect; the egg breaks while the ball rebounds undamaged. Most living animal soft tissue has a consistency much closer to that of the rubber ball than to that of the brittle egg shell. This simple experiment demonstrates the fallacy in the common assumption that all kinetic energy "deposited" in the body does damage.

The assumption that "kinetic energy deposit" is directly proportional to damage done to tissues also fails to recognize the components of the projectile-tissue collision that use energy but do not cause tissue disruption. They are 1) sonic pressure wave, 2) heating of the tissue, 3) heating of the projectile, 4) deformation of the projectile, and 5) motion imparted to the tissue (gelatin bloc displacement for example).

The popular format for determination of "kinetic energy deposit" uses a chronograph to determine striking velocity and another to determine exit velocity. A 15-cm thick block of tissue simulant (gelatin or soap) is the target most often used. This method has one big factor in its favor; it is simple and easy to do. As for its validity, the interested reader is referred to wound profiles shown in Figs 1-7. Comparing only the first 15 cm of the missile path with the entire missile path as shown on the profiles shows the severe limitation of the 15-cm block format. The assumption by weapons developers that only the first 15 cm of the penetrating projectile's path through tissue is of clinical significance (64) may simplify their job, but fails to provide sufficient information for valid prediction of the projectile's wounding potential. The length of bullet trajectories through the human torso can be up to four times as long as those in these small blocs. Even if this method were scientifically valid, its use has been further flawed by nearly all investigators who have included the M-16 rifle bullet in those projectiles tested. This method assumes that the projectile's mass remains constant through both chronographs. The M-16 routinely loses one third of its mass in the form of fragments which may remain in the target (see Fig 2). The part of the bullet that passes through the second chronograph screens weighs only about two-thirds as much as the intact bullet that passed through the first set of screens. No provision is made for catching and weighing the projectile to correct for bullet fragmentation when it occurs. The failure to correct for loss of bullet mass can cause large errors in "energy deposit" data (8).

Surgeons sometimes excise tissue from experimental missile wounds that is, in their judgment, nonviable and compare the weight of tissue excised with the "kinetic energy deposited" (65). A surgeon's judgment and his technique of tissue excision is very subjective, as shown by Berlin et al (66), who found in a comparison that "One surgeon excised less tissue at low energy transfers and rather more at high energy transfers than the other surgeon, although both surgeons used the same criteria when judging the tissues." None of these experiments included control animals to verify that tissue the surgeon had declared "nonviable" actually became necrotic if left in place. Interestingly, all studies in which animals were kept alive for objective observations of wound healing report less lasting tissue damage than estimated from observation of the wound in the first few hours after it was inflicted (43-47, 67, 68). In a study of over 4,000 wounded in WW II it was remarked, "It is surprising to see how much apparently nonvital tissue recovered" (69).

Anyone yet unconvinced of the fallacy in using kinetic energy alone to measure wounding capacity might wish to consider the example of a modern broadhead hunting arrow. It is used to kill all species of big game, yet its striking energy is only about 50 ft-lb (68 Joules)-- less than that of the .22 Short bullet. Energy is used efficiently by the sharp blade of the broadhead arrow. Cutting tissue is far more efficient than crushing it, and crushing it is far more efficient than tearing it apart by stretch (as in temporary cavitation).

I can play the copy/paste game from the internet too

Effective Game Killing

Effective game killing- How bullets kill and where to aim to ensure a fast clean kill.

www.ballisticstudies.com

 

[backcountry_hunter]

Fair enough Dr. Fackler is now disproved by a self proclaimed: "Outside of my hunting career, my work roles centered around either farming, stainless steel engineering or nightclub security work which was an ongoing role."

seems legit

 

[Formidilosus]

But interesting you mention that. Hornady recommends 1700ft/lb of energy for expansion of the eldx.

Please cite where Hornady recommends 1,700ft/lb of energy for expansion of the ELD-X.

 

[Vandy321]

Fair enough Dr. Fackler is now disproved by a self proclaimed: "Outside of my hunting career, my work roles centered around either farming, stainless steel engineering or nightclub security work which was an ongoing role."

seems legit

Multiple doctors are cited in that research/article

 

[Vandy321]

Please cite where Hornady recommends 1,700ft/lb of energy for expansion of the ELD-X.

Called their tech. Assuming you are capable of doing the same.

 

[Formidilosus]

Called their tech. Pick up the phone.

I know their ballisticians. You misheard, or their tech incorrectly spoke. ELD-X’s need 1,700-1,800 feet per second at impact to upset.

 

[LongWayAround]

Will the jacket and core of ELD-X bullets separate since they're not bonded? - Hornady Manufacturing, Inc

ELD-X Bullet Jacket/Core Separation High-velocity impacts may occasionally cause the ELD-X bullet jacket to roll back past the InterLock ring during penetration, leading to jacket core separation as the bullet comes to rest. When bullets stop inside a...

www.hornady.com

https://www.hornady.com/assets/site/hornady/files/resources/ELD-X_ELD-Match_Technical_Details.pdf

I didn't have time to read super deep into either of these, but a quick skim revealed no mention of energy. Numerous mentions of velocity for eld-x expansion though...

 

[Vandy321]

I know their ballisticians. You misheard, or their tech incorrectly spoke. ELD-X’s need 1,700 feet per second at impact to upset.

You seem to have access to more than most, Form, why not put some bullets into gel at 600-800 yards from 6mm, 7RM, 300wm and see what the controlled variables show? Could solve the debate with actual data

 

[Formidilosus]

You seem to have access to more than most, Form, why not put some bullets into gel at 600-800 yards from 6mm, 7RM, 300wm and see what the controlled variables show? Could solve the debate with actual data

It’s been done. You just refuse to listen.


Yes, given identically constructed projectiles and impact velocities, heavier and wider bullets have more potential and will tend to crush/damage more tissue. However, that is not the whole answer. All else being equal, getting a wider wound channels reduces total penetration, and gaining penetration reduces the width of the wound.
Therefore, it is entirely possible to get sufficient penetration and a wider wound with certain 6mm bullets, than lots of 7mm bullets. Yes, if you maximize the 7mm it will be a larger wound- but when do you stop? 30cal will be larger than 7mm, 338 can be larger than 30cal, 375 can be larger than 338, etc, etc. The answer is you stop when sufficient penetration and wound size is achieved- and that can be done for most with a 6mm. Or 6.5. Or 7mm. Or .224 in some cases.
Yet, that’s not what most people do- they move up in “caliber/cartridge” and then “choke” the larger chambering down by using harder bullets which then cause smaller wound channels.


1). Can 6mm bullets reliably penetrate sufficiently in large game- yes.

2). Can 6mm bullets create wounds that destroy enough tissue that most people will think they are “too much”- yes.


I’m very large sample sizes of shot game animals at ranges far enough with suppressed rifles that the animal doesn’t react to the report- in pure lung shots the average time to incapacitation is mainly controlled by how large the wound is- and like constructed bullets impacting at similar velocities produce nearly identical results- I.E., 20-60 seconds for incapacitation. That’s regardless of .224, .243, .264, .277, .284, .308, etc. For terminal ballistics, once a bullets achieves penetration through both lungs, it has penetrated sufficiently and no deeper penetration capabilities is of benefit. After that, the larger the temporary and permanent crush cavities are, the faster animals succumb. But, it isn’t linear- a 8 inch TC doesn’t measurably decrease the incapacitation time of game animals over a 7 inch TC. Etc, etc.

So then, unless someone is purposely maximizing tissue damage regardless of lost meat (if they are, large 30 or 338cals with very soft projectiles are the answer), or needing a farther expansion range, all someone is gaining is more recoil with larger cartridges. Killing and recovering animals efficiently and with the least amount of drama is way more than a bigger round- once adequate terminal performance is achieved, shootability and repeatability factor heavily.

The largest money maker in killing quickly is placement with adequate penetration with a bullet that upsets violently and fragments early and continuously along its wound path. In other words, exactly opposite of marketing and adds.

 

[Vandy321]

It’s been done. You just refuse to listen.


Yes, given identically constructed projectiles and impact velocities, heavier and wider bullets have more potential and will tend to crush/damage more tissue. However, that is not the whole answer. All else being equal, getting a wider wound channels reduces total penetration, and gaining penetration reduces the width of the wound.
Therefore, it is entirely possible to get sufficient penetration and a wider wound with certain 6mm bullets, than lots of 7mm bullets. Yes, if you maximize the 7mm it will be a larger wound- but when do you stop? 30cal will be larger than 7mm, 338 can be larger than 30cal, 375 can be larger than 338, etc, etc. The answer is you stop when sufficient penetration and wound size is achieved- and that can be done for most with a 6mm. Or 6.5. Or 7mm. Or .224 in some cases.
Yet, that’s not what most people do- they move up in “caliber/cartridge” and then “choke” the larger chambering down by using harder bullets which then cause smaller wound channels.


1). Can 6mm bullets reliably penetrate sufficiently in large game- yes.

2). Can 6mm bullets create wounds that destroy enough tissue that most people will think they are “too much”- yes.


I’m very large sample sizes of shot game animals at ranges far enough with suppressed rifles that the animal doesn’t react to the report- in pure lung shots the average time to incapacitation is mainly controlled by how large the wound is- and like constructed bullets impacting at similar velocities produce nearly identical results- I.E., 20-60 seconds for incapacitation. That’s regardless of .224, .243, .264, .277, .284, .308, etc. For terminal ballistics, once a bullets achieves penetration through both lungs, it has penetrated sufficiently and no deeper penetration capabilities is of benefit. After that, the larger the temporary and permanent crush cavities are, the faster animals succumb. But, it isn’t linear- a 8 inch TC doesn’t measurably decrease the incapacitation time of game animals over a 7 inch TC. Etc, etc.

So then, unless someone is purposely maximizing tissue damage regardless of lost meat (if they are, large 30 or 338cals with very soft projectiles are the answer), or needing a farther expansion range, all someone is gaining is more recoil with larger cartridges. Killing and recovering animals efficiently and with the least amount of drama is way more than a bigger round- once adequate terminal performance is achieved, shootability and repeatability factor heavily.

The largest money maker in killing quickly is placement with adequate penetration with a bullet that upsets violently and fragments early and continuously along its wound path. In other words, exactly opposite of marketing and adds.

Can you post the ballistics gel comparisons you say have been done? I may have missed the link.

 

[Formidilosus]

Can you post the ballistics gel comparisons you say have been done? I may have missed the link.

Unfortunately most are not publicly available.

Hornady, federal tactical, Speer, etc. have some publicly available images on their websites of high velocity impacts. So far there have been no publicly available legitimate testing with properly calibrated 10% ballistics gel at full range; at least that I am aware of.


Take the info or not. Those 6mm bullets weren’t used until sufficient testing had been completed to have a good idea of what the results would be.

 

[ericwh]

... Hornady recommends 1700ft/lb of energy for expansion of the eldx. At those same environmental and speeds, the 6mm has 1724 ft/lb at 50 yards (3000 fps from the muzzle) ...so not even meeting the min suggested for expansion at 100 yards...

You just showed everybody you don't know what you're talking about.

Thresholds for expansion are in units of velocity, not energy. Saying a 6mm won't expand at 100y... Goooooolly.

May I humbly suggest you just let it go?

 

[Vandy321]

You just showed everybody you don't know what you're talking about.

Thresholds for expansion are in units of velocity, not energy. Saying a 6mm won't expand at the muzzle... Goooooolly.

May I humbly suggest you just let it go?

But saying a 6mm is a better elk cartilage than a 7RM with studies that somehow can't be released to the public.

Are we working with Pfizer here or actually publicly available verifiable data? I've got meat in the freezer from multiple calibers, and never did I argue a 6mm wouldn't kill. I can say that it's not the first rifle I'd grab for an elk hunt.

And I can only repeat what the hornady tech passed along, you have issues with it, call them to verify, or don't, I really dont care.

The sad part is, this thread will inevitably lead to dudes who are not capable of great shot placement at range, taking their. 223 out into the elk woods and wounding/not recovering animals. Can it kill, sure, is it the best caliber for elk, probably not.

 

[Woodrow F Call]

But saying a 6mm is a better elk cartilage than a 7RM with studies that somehow can't be released to the public.

Are we working with Pfizer here or actually publicly available verifiable data? I've got meat in the freezer from multiple calibers, and never did I argue a 6mm wouldn't kill. I can say that it's not the first rifle I'd grab for an elk hunt.

And I can only repeat what the hornady tech passed along, you have issues with it, call them to verify, or don't, I really dont care.

The sad part is, this thread will inevitably lead to dudes who are not capable of great shot placement at range, taking their. 223 out into the elk woods and wounding/not recovering animals. Can it kill, sure, is it the best caliber for elk, probably not.

Part of the argument for smaller bullets is less recoil resulting in better shooting.

If you can't shoot, increasing caliber/energy isn't really the answer.

 

[Formidilosus]

But saying a 6mm is a better elk cartilage than a 7RM with studies that somehow can't be released to the public.

At no point did I say that. May I remind you, that you asked the first question about why not 6mm’s- I answered. I have never addressed better or worse, merely that 6mm can be a perfectly viable caliber.

The sad part is, this thread will inevitably lead to dudes who are not capable of great shot placement at range, taking their. 223 out into the elk woods and wounding/not recovering animals. Can it kill, sure, is it the best caliber for elk, probably not.

If someone isn’t capable of great shot placement, going larger doesn’t help them- it’s hurts them. Every human alive can and will shoot any given rifle with less recoil better, than that same rifle with more recoil. If I were hunter that didn’t take shots beyond 450’ish yards, I wouldn’t shoot anything but a 223 with 77gr TMK’s for everything in NA- that is from actual use killing hundreds of a animals with every caliber mentioned and comparing results.

 

[LongWayAround]

The pdf I linked has several images of ballistics gel impacts. Maybe not exactly the comparisons and distances requested though. They're all .30cal but show the response of various bullets at high and low velocity impact. Energy is not mentioned.

I don't have a dog in the fight but, I personally shoot my 6.5CM a lot better than my 7RM.

 

[KineKilla]

Both of these came from my 7mm. One was on a deer at about 175yds, the other is from a cow elk at 100yds or less.

Knowing nothing else about the rifle, bullet or ballistics, what would your takeaways be?

Mine are that there was still plenty of energy, speed etc. left in each to function well from much farther away.


BTW, these are my 160gr Accubond handloads moving 2,945fps at the muzzle. Both lost what I consider to be excessive weight but I attribute that to the closeness of each shot. Nonetheless, quite effective.

Sent from my SM-N976U using Tapatalk

 

[35WhelenAI]

Barnes 200 X and 250 X, 35 Whelen AI.

200 X @2900 fps mv, quartering toward, recovered under the hide of the opposite rear quarter. 225 yds, cow elk.

250 X @2575 fps mv, quartering away, recovered in opposite side lower neck meat. 60 yds cow elk.

.748" expanded diameter, both 100% wt retention. In the frontal expanded picture of the bullets, can't tell which is which.

The side view picture shows unfired examples of each bullet, with the expanded bullets, and a 200 TTSX for length comparison. Haven't recovered a TTSX on an elk, but haven't had a shot with a the hard quartering angle yet.

Expansion (velocity) and penetration (momentum) with all else equal are needed to put the vitals out of commission. Energy is the one left out of the room.