45-70 vs 458 penetration

Purely from a scientific standpoint:

It’s well recorded that a slower hardcast 430gr .458 bullet such as 1500fps will penetrate much deeper than a 2100fps one, for various factors, bullet deformation and fluid dynamics being the most obvious.

However when considering a hard target such as a buffalo, how deep would the bullet need to penetrate to be considered effective and would a fast bullet penetrate to this depth and at the same time also impact more energy vs a slower bullet that would go much deeper, but with less kinetic impact on the animal ?

If the slow bullet goes more than deep enough, would it still come short of a “proper” shot due to the lower energy dumped into the animal and thus not being effective enough as one would hope when facing a buffalo ?

Which begs the real question; should you try to push your bullet as fast as possible for maximum energy or should you stick to a lower speed for (theoretically) deeper penetration ? The speed being calculated at the target, not at the muzzle.

Similar results: several years ago I tested a bunch of .30" bullets for terminal performance. These were various expanding bullets fired at 30-06 & 300 Wby velocities into water-filled gallon plastic jugs. Penetration for the cup&core bullets at 30-06 velocity ran about 4 jugs. 300 Wby made it into 5. The premium bullets of the time- Nosler Partition and bonded core made it to 7-8 jugs. Now, to your topic- I also fired some lead round balls at considerably slower velocities. they were virtually unstoppable. the stand that I had held 8 jugs, each 6" in diameter, so to pass through 8 the bullet needed to go through 4 feet of water. As you note, the penetration with your bullets was similar to my results. the big difference was in disruption. the jacketed high velocity bullets would completely destroy #1,2 jugs and significantly disrupt #3 and the magnums #4- Water splashes several feet into the air. The slow round lead bullets barely moved the jugs- acting more like an arrow. Pushing through the jugs, making an entry and exit hole the size of the bullet from which water ran out. The shock would have been virtually non-existent, for an animal unless it hit significant bone, the wound may have been fatal but not quick.

However when considering a hard target such as a buffalo, how deep would the bullet need to penetrate to be considered effective and would a fast bullet penetrate to this depth and at the same time also impact more energy vs a slower bullet that would go much deeper, but with less kinetic impact on the animal ?

If the slow bullet goes more than deep enough, would it still come short of a “proper” shot due to the lower energy dumped into the animal and thus not being effective enough as one would hope when facing a buffalo ?

For a bullet to be effective, vital organs must be destroyed or at least impaired in their functioning, either directly by the bullet or indirectly by the bullet's shock waves. How deep the penetration must be depends on the question of how quickly the animal should die. Even relatively minor organ damage can lead to the death of the buffalo after a longer period of time. However, if the aim is to kill the animal quickly, then a shot “into the engine room” must hit either the heart and/or the lungs with the bullet and cause sufficient damage. I would consider this to be the minimum penetration required.


Which begs the real question; should you try to push your bullet as fast as possible for maximum energy or should you stick to a lower speed for (theoretically) deeper penetration ? The speed being calculated at the target, not at the muzzle.

If the faster bullet penetrates vital organs, it will – assuming the appropriate bullet type – be more effective due to its higher energy output than the slower bullet, which may penetrate even further into the animal's body.

Great answers, thanks for the good explanations.

What youre describing is energy transfer or work, which is a function of the bullets energy and the resistance it encounters. In essence we want to do as much work as possible on the important parts of the animal (structural, nervous, circulatory, respiratory). If you were to walk up to a paralyzed buffalo and slowly shove a sharp pointy half inch rod through it, obviously it would bleed to death or suffocate eventually, but it would take a while. Conversely, hitting him with a blunt .458 tungsten slug at 6,000 fps would obviously have very violent and instantaneous effects.

All that to say, its not really possible to say. Ideally the bullet would impact the animal, break the on-side structure, penetrate to the important parts, halfway fragment, and the other half carry enough juice to break the important structure on the other side. Thats why partitions are so loved, they pretty much do that as reliably as can be expected.

Since we cant realistically expect that it becomes a compromise and a decision about what you want. Do you want to break bones or do you want violent upset and mass destruction of vital tissue? Most buffalo hunters chose the former because while it will kill slower, it generally is more predictable.

The slower load will probably penetrate better in tissue. Will it penetrate bone better? How do we make it fragment in the lungs, which are 50% air? All that to say its really difficult to make a buffalo bullet be perfect. Theres too much variation in density and resistance in a given cross-section of the animal and it changed wildly with the angle.

Garett Cartridge has some interesting info on this subject on their website.

The Linebaugh Pentetration tests used bovine bones and wet newspaper. Hard cast 45-70 is a powerful tool.

There are many threads that will give you data. Michael458 did extensive tests on velocity vs penetration. From his data with identical brass solids, penetration peaks around 2350 fps. 45-70 will kill buffalo but in a charge situation, it is a little dodgy.

Nhoro said:

There are many threads that will give you data. Michael458 did extensive tests on velocity vs penetration. From his data with identical brass solids, penetration peaks around 2350 fps. 45-70 will kill buffalo but in a charge situation, it is a little dodgy.

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Everything is iffy in a charge situation.

Dav said:

Purely from a scientific standpoint:

It’s well recorded that a slower hardcast 430gr .458 bullet such as 1500fps will penetrate much deeper than a 2100fps one, for various factors, bullet deformation and fluid dynamics being the most obvious.

However when considering a hard target such as a buffalo, how deep would the bullet need to penetrate to be considered effective and would a fast bullet penetrate to this depth and at the same time also impact more energy vs a slower bullet that would go much deeper, but with less kinetic impact on the animal ?

If the slow bullet goes more than deep enough, would it still come short of a “proper” shot due to the lower energy dumped into the animal and thus not being effective enough as one would hope when facing a buffalo ?

Which begs the real question; should you try to push your bullet as fast as possible for maximum energy or should you stick to a lower speed for (theoretically) deeper penetration ? The speed being calculated at the target, not at the muzzle.

Click to expand...

@Dav
This is a question that hunters and bullet manufacturers have been trying to solve for eternity.
Do we sacrifice velocity for penetration or is penetration more important than velocity/energy.

The aim is to have the perfect combination of both, virtually impossible in the the days of yore with cup and core and old round nose solids.

Fast forward to today with the likes of swift A frame, north fork, Woodleigh and the plethora of monos like Barnes and others and we have a pretty good compromise of higher velocities, better bullet construction and designs and we almost the epitome of the ideal mix of devastation and penetration and velocity to take game.
Bob

The airgun community are getting complete pass throughs on deer using pure lead bullets at typically less than 900fps. It’s an interesting topic. This is in calibers from .308-.72.

Dav said:

Purely from a scientific standpoint:

It’s well recorded that a slower hardcast 430gr .458 bullet such as 1500fps will penetrate much deeper than a 2100fps one, for various factors, bullet deformation and fluid dynamics being the most obvious.

However when considering a hard target such as a buffalo, how deep would the bullet need to penetrate to be considered effective and would a fast bullet penetrate to this depth and at the same time also impact more energy vs a slower bullet that would go much deeper, but with less kinetic impact on the animal ?

If the slow bullet goes more than deep enough, would it still come short of a “proper” shot due to the lower energy dumped into the animal and thus not being effective enough as one would hope when facing a buffalo ?

Which begs the real question; should you try to push your bullet as fast as possible for maximum energy or should you stick to a lower speed for (theoretically) deeper penetration ? The speed being calculated at the target, not at the muzzle.

Click to expand...

If your logic is correct, we all should be hunting with FMJ or armor piercing projectiles.

Twraska said:

If your logic is correct, we all should be hunting with FMJ or armor piercing projectiles.

Click to expand...

I mean isn’t what 50BMG was designed for ? The ultimate buffalo cartridge ?

5shot said:

The Linebaugh Pentetration tests used bovine bones and wet newspaper. Hard cast 45-70 is a powerful tool.

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So I’m playing with some 423gr RNFP GC hardcast, reading about 24BHN on the Brinell Hardness scale (SAECO 10-11 test result) and so far I’m pushing them out at 1750fps in my 1895 19” barrel. I’m setting up a water bucket test to evaluate how the bullet holds up, to see if there’s any point in making it go any faster. Shoulder bones are definitely the biggest concerns when it comes to penetration on the bigger animals from what I’ve seen and I like to know what to expect from a certain bullet as I spread the 45-70 gospel onto African game.

Put on some safety glasses,put one on the garage floor and smack it on the nose with a 3lb sledge. If it doesn’t shatter, you’re probably good.

Brian Pierce wrote up a Cape Buffalo hunt when using a Marlin M1895 in .45/70. He used a solid Buffalo Arms ammo in a 400gr.(I think that was the make & weight). He shouldered the bull, but also killed a cow on the other side that was not seen prior to the shot - as it was written up. That cost another few thousands of $$ I think. Trying to remeber all the nitty gritty of the article. The mv. of that load was 1,700fps + a bit of change. I still have that article in my data" 3-ring on .45/70 loads. In the article, he covers the 3 levels of performance WITH pressure, depending on the rifle.

As far as solid lead bullets, if you have access to the old antimony WW's with the crimp-on weights, not the zinc nor the pure lead ones for mag wheels, you can cast bullets in the WW, then harden them. They will test out from about 25 brinell to as high as 34, depending on your method and temp used. Just dropping them into a water bucket(towel on the bottom), in 12 hours they will obtain maximum hardness. Put a sliced towel over the bucket, so they fall the the slit into the water. That way no water will splash into your melted lead. THAT would be catastrophically dangerous. Been there, done that. Don't do it. If you wait 12 hours, then size and lube, the lead will soften on the move/sized metal sides. If you dry them, then lube and size immediately, they will harden properly. Ross Seyfried used a hardened lead bullet in the .50 Linebaugh he used on a cape buffalo. It worked. I don't remember the country he did this in.
Good luck. With a good load, the .45/70 will work. In Safari Hunter's Journal, an American hunter shot an Eland with medical problems(cull) with an Umarex Hammer .50 cal. air rifle using a 350g.r flat point bullet. The bullet was found bulged under the skin of the off side, just behind the elbow. It was delivered into the off side. The Eland went maybe 40yards after the shot. If you want to see the vid. google Umarex Hammer .50 on Eland.

Dav said:

However when considering a hard target such as a buffalo, how deep would the bullet need to penetrate to be considered effective

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Real world test on putting down crippled cattle using 405gr Lee flat nose cast projectiles that were also paper patched and pushed at 1,800fps in my Martini Enfield 45/70. The animals would have weight 800 to 900Kg. They were both shot at approximately 50m front quartering shot and side on shot. Both animals dropped on the spot and did not require follow up shots.
Neither bullet exited, The side on shot, the bullet entered immediately behind the nearside leg and was found under the skin on the far side mushroomed out to about 20mm in diameter, no leg or shoulder bones were impacted.

Dav said:

Which begs the real question; should you try to push your bullet as fast as possible for maximum energy or should you stick to a lower speed for (theoretically) deeper penetration ? The speed being calculated at the target, not at the muzzle.

Click to expand...

I think this has been tested, so I will point you to direction where to look.

When they invented 458 win mag, it was on tests performing well, but they reduced the barrel length on m70 and reduced load of cartridge. This lead to underperformance and failures on dangerous game with 458 win mag and brought the bad reputation of the cartridge.
All you need to do is check what were the underperforming actual velocities of that time.

Advertised velocities of that time: 2150 fps. actual velocities 1850 - 1950 fps.
The time when nobody had chrony or labradar. They trusted factory declaration.

This is wikipedia on 458 win mag:
By 1970, issues with the cartridge began to surface. Winchester had been using compressed loads of ball powder as a propellant for .458 Winchester Magnum. Due to clumping of the powder charge and the erratic burn characteristics associated with such loads, performance of the cartridge came into question.

A Brinel 12, .682" 466gr. round ball will pen from one side of a bull moose, breaking off a 6" piece of rib, then driving through both lungs and smash the 3" diameter leg bone, then end up under the hide, that side, slightly expanded. That 6" piece of rib, sliced the lungs and stuck between 2 ribs on the off side. Initial vel. 1,550fps. Range 95 to 100yards. The moose went no where, but down.
Thus, I can see where if the bullet is not brittle, but tough, it has a good chance of doing work. This is why straight Linotype makes poor big game bullets. It is brittle at 20 to 21 brinel. It's really high antimony makes it brittle. Lead/tin mix's highest brinel is about 16, in a 10:1 mix.
I don't think this alloy is as brittle as Linotype, but won't match the penetration of even harder mixes of straight WW alloy that is hardened.
I shot a WW ball from that rifle into a 4" thick concrete block of cement. Same "moose" load. The block of concrete was about 20" long and 12" wide. It was reduced to 3" and smaller chunks from a range of 50yards. The ball was in the debris - I still have it, expanded to about .90 calibre & very near it's original weight of 466gr. I would suggest that a WW bullet, restricted in vel. to about 1,800fps, would likely do fairly well on it's own, if .45 calibre or larger.
If interested in hardening cast bullets, you can google the process, I assume. I started hardening my cast bullets back in about 1977/8. Veral Smith's little blue book, "JACKETED PERFORMANCE FROM CAST BULLETS" was my inspiration. From my .375 BRNO, I ran 275gr. cast bullets at 2,700fps for 1 1/2" groups @100yds. at the Barnet Range in Burnaby.