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| One of Us |
One of our fellow forumites has been kind enough to present a web page that calculates the penetration index of various calibers. http://home.t-online.de/home/nhansen/penetr.htm These numbers give a pretty good indication of what combinations penetrate deeply and what ones do not. I apologize that the 45-70 with a 400 grain bullet is not listed, but the 458 win with a 500 grain bullet at 1900 is listed, and it makes a poor showing. Since we know that the 45-70 achieves 1800 or a bit more with a 400 grain bullet, we can expect its penetration index to be around 70, off the chart at the bottom end for poor penetration. | ||
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| one of us |
Why are the penetration values of the 325 grain 375 H&H and the two 416s highlighted in red? They have respective values that are not the highest listed. Also, it would be useful to see some of the more popular calibers, such as 270 Win and 300 Win Mag, for comparison purposes. It may be assumed they will fall between 100 and 137. | |||
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| <Rusty> |
Now, we are talking about a 45/70 bullet out of a Marlin Lever Action Rifle? I thought so! | ||
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| <North of 60> |
These numbers are using a formula found in A Square's "Any Shot You Want" a good read. The penetration index is calculated by dividing kinetic energy with the area of the bullet and multiplying the result by the sectional density. It assumes the use of a solid which does not deform in any way. A Square really recommend 2400ft/sec as the ideal velocity for African Big Game with good bullets that don't deform. In their experience this velocity greatly assists in penetration. A 540 grain. 458 bullet at 1500Ft sec gives a penetration index of about 60. about 40% less than the .458. | ||
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| one of us |
500 grains--------along with the "poor showing" of the .458 , the 470 nitro express and the .404 turned up virtually the same numbers...... | |||
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| One of Us |
quote:With a 500 grain bullet? | |||
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| <Harald> |
500grains, this Penetration Index, like any number of other shortcut formulas is flat wrong. Plain and simple. Get some actual data. No serious terminal ballistics calculation involves "sectional density". That nonsense was cooked up by a bullet manufacturer. If penetration alone is the measure of merit for buffalo killing then a 45-70 suffers nothing in a side by side comparison to any bigbore made. That comes down to bullet design above all. Certainly not velocity. Now velocity is important for cavitation and the bigger bores that in many cases do not penetrate as well as some 45-70 loads will do more damage because they have more energy to expend and it has to go somewhere if its not going into penetration. But a 45-70 has way more penetration than is required to slay a buffalo or an elephant without any wobbly knees. It will easily do it every time - with proper aim and the right bullet. As far as that goes, the .303 British and a host of other smallbores have all the stuff required to penetrate unfailingly as much as required and more. With more powerful guns, though, you don't have to be quite as fussy about the load. [ 06-26-2002, 07:12: Message edited by: Harald ] | ||
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| one of us |
It is always interesting to see the imaginative ways that people try to quantify a bunch of numbers to mean something or another. Heck, you could put "Big Mac explosion test" on top of a chart and it would have about as much meaning. Putting numbers on paper just don't cut it when you're talking about real, live, flesh-and-blood targets. Only real in the field experience will convince me of the veracity of certain cartridges over others and there has certainly been plenty of people with plenty of time and experience to know what works and what doesn't. I'll just trust that experience instead of trying to duplicate it myself. However, charts are good for one thing- they make terrific targets!- ![[Wink]](images/icons/wink.gif){kind=icon} - Sheister | |||
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| <Peter> |
500 grains. Your post said 1800fps with a 400 grain bullet. I have never shot a 500 grain bullet in my 45/70. Peter. | ||
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| one of us |
A 45-70 from a levergun gets 2,000 FPS with a 430 grainer. Either handloads or Bufalo Bore Ammo can do this. Not sure of Cor-Bon, HSM, etc. Even leser speeds have shown major penetration. Revolver hunters, shooting heavy HC bullets prove this. Also, check out Ross Seyfried's artical concerning penetration of round nose/pointed nose/flat nose bullets, in the latest Handloader magazine. He tells of a flat pointed HC bullet, at revolver speeds or about 2,000 FPS, penetrating deeply and going straighter, then round nose solids, and doing a lot of damage. Is there a person who can dis-prove what Seyfried says? No. Instead, they'll make snide remarks as to Seyfried not being god, or some odd thing, because they can't win over his statements. You watch and see... ~~~Suluuq | |||
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| <Safarischorsch> |
[I disagree... The sectional density is important. i would never shot on an elephant with the 45/70. If i had to chosse between 7mm Mauser and the 45/70 i would take the mauser with solids like kramoja bell. Of course good aiming is absolutly neccessary. | ||
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| one of us |
Geesh, guys, I love the 45-70, but is it a good elephant or buffalo cartridge? I think any unbiased individual would say no. Will it kill one with the proper loads and bullet placement? Absolutely and so will many "lesser" rounds, but that doesn't mean it is a good choice for the job. Nor does it mean it has the "swat 'em" power necessary if things go wrong. The object is to kill them, not give them a fair chance to kill you. But, it is your money, your hunt, and if the PH will go along with it, go for it. | |||
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One of Us |
Guys: In the latest issue of Handgunner magazine there is an article about penetration and the big bore handgun and rifle cartridges using those hard cast lead bullets. One of the handguns was a 45-70 and the other ones beign 454 Casull, 475 Linebaugh, etc. They even threw in a 500 Nitro Express Double and according to those tests, the handguns with velocities aroud the 1850 fps mark, actually out-penetrated the 500 NE using solids!!!! Interesting reading. | |||
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| One of Us |
quote:Looks like we'll just have to disagree. The 45-70 fails miserably in the penetration department compared to modern competent calibers like the 458 lott. | |||
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| One of Us |
Peter, you misread. The 400 grain .458 bullet falls short of the .300 mark in sectional density, therefore it is disqualified. The 450 and 500 grain bullets hit the mark on sectional density. Can you get 2100 fps out of either in a 45-70? No. The 458 win mag has failed with the 400 grain bullet at 2200 fps and with the 500 grain bullet at 1800-1900 fps. And those numbers are better than a 45-70 will ever do. | |||
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| <Norbert> |
Some comments on missleading and wrong posts above: Please read all relevant articles and statements about penetration at www.grosswildjagd.de penetr.htm is only one article, most are now in english. --The Penetration Index (formula from Alphin) is a valuable figure to compare the relative penetration ability of non-deforming bullets for a given medium. It has nothing to do with killing power or knock down ability or other, most useless figures given in literature. It is a relative figure and not linearily correlated to the penetration depth in a target. That means a bullet with a PI of 70 travels not half the way of one with a PI of 140. The real ratio depends on the energy dissipation on the way through the target. It is impossible to calculate the penetration depth in an animal by theoretical figures.-- I will call this PI in the future Penetration Power as it is only considering one aspect. The full story how penetration is accomplished is given under the title SuperPenetrator. The red highlighted numbers are on bullets with superior penetration in calibers which the average hunter can handle easyly. quote:A statement from the website: In general, we observe an increasing Penetration in the following order: Round nose with semispherical head, konventional FMJ with a small ogive and flattened nose, real flat nose bullets, bullets with cavitator disk. About indexes: Because the listed data of a cartridge (weight, velocity, energy and caliber of the bullet) give not directly a measure of its efficacy, since decades authors tried to formulate numbers which reflect its quality. The basic physical data are only weight, velocity and diameter (or related figures like cross sectional area, radius etc). Physically meaningful calculated data then are the momentum and kinetic energy, which also do not lead to sufficient information on its behaviour in animals. So authors tried to weight these data with som other figures creating a lot of "indexes". But all these indices are overrated or misinterpreted, esp. when expressions are used like "killing power"or "knock out value". Some are useless, some are only meaningful if limited to a small range of caliber, weight etc. But than we can also judge from our experience. A bigger bore with near the same velocity is better than the small bore......and so on. Alphin�s PI is only used to have an impression on the penetration of solids. Nothing more. Not its interaction with the animal. Not the killing power of a needle. quote:I think this is true nonsense. SD is not used by one manufacturer, but cited in many ballistic tables and articles. Unfortunately the nominal figure is a little inaccurate, using the diameter squared instead of the radius squared times pi. But physically it is very meaningful and is related to the force, which is needed to decelerate the bullet in the target, which among others is a very important aspect. BTW. I tested penetration on living and just killed animals and found the PI describes the penetration power for a given bullet construction very well. | ||
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| one of us |
Norbert... Do I have this right? In your views, a flat point bullet penetrates more then a round nose solid? (But obviously less then a SP bullet) This is what Seyfried says too, and has proven it. And to think Seyfried advocates hardcast bullets "at revolver speeds", with a very wide meplat (flat nose), the very same bullet design and material used in a 45-70! This goes to show, the 45-70 is updated simply due to the bullet used, not because it came from a levergun, or from a 120 year old BP case design. Its the bullet that does the killing. And a hardcast bullet with a wide meplat does it will. Too bad some still won't accept this. Its because they don't understand it. Compare the SP disc (flat point), to a HC flat point. Both do nearly the same thing, but obviously the SP, being harder and stronger material, will hold it's disc shape(flat point) longer, thus drive deeper. BTW I never said a levergun was best as a DGR, nor that it was best, period, for DG. I merely said it had been done, will continue to be done. Some make this out to be more then it really is. ~~~Suluuq | |||
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| <Safarischorsch> |
quote:Of course they do! Because sectional density an good designed bullets are important... | ||
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| one of us |
Click on this link the open minded among us might find it very intresting.... http://www.sixgunner.com/linebaugh/penetration_test.htm [ 06-28-2002, 09:00: Message edited by: jnc91 ] | |||
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| <Norbert> |
Even if open minded, The Linebaugh Seminar penetration tests are not clear enough for a sound statement. It is nothing said about the distance to the target. The 500 rifle data show the tumbling of the bullets due to ineffective stabilisation. Bullets from handguns are usually better stabilized for close distances. Nothing to learns from this test. | ||
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| <Harald> |
Norbert, You stated that the PI does not directly (linearly) correlate to the penetration depth and also that you tested the PI and found a strong correlation between the PI and the "penetration power". Can you explain this? What correlation is there, if not with penetration depth or does the PI correlate to a higher or lower order? If the latter why not simply amend the equation with the correct order? 500 grains, et. al, Just to be clear I am not proposing that a 45-70 possesses any potential not possessed by cartridges with more powder volume. With similar bullets they can do similar things. There seems to be a point where most bullet designs begin to "stack" in penetration. It isn't perfectly linear with velocity, even for solids. The drag function (I don't mean drag force) is at least a linear function of velocity and tends to keep pace with the momentum pretty well, reducing what would otherwise be a linear gain in penetration. [ 06-28-2002, 20:33: Message edited by: Harald ] | ||
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| <Norbert> |
Harald, I never said that I found a strong correlation between the PI and penetration. By chance I found it in one test medium, but that is not relevant. I don�t know the drag functions in various media and it is impossible to calculate the penetration depth in an animal by theoretical figures. But the PI is a valuable figure to compare the relative penetration ability of non-deforming bullets for a given medium and to give the hunter a feeling how to look at the cartridges. And I think it is not worth to do more research for finding new, even better formulas, as they will never depict the whole truth. A bullet with a PI of 98 doesn�t penetrate an elephants head at distinct angles, whereas a bullet with a PI of 130 penetrates in all directions. And that is the information a hunter wants. | ||
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| one of us |
Norbert, I don't understand how this study can be said to prove nothing. Even though wet paper doesn't exactly duplicate large heavy animals it does give the relative penetration of calibers in the same medium and that it seems tells a lot. Furthermore assuming the 500 and some other rounds tumbled because of poor stabilization at close range I think that certainlhy tells us a lot about that rifles performance as a stopper since a stopper is primarilary expected to save your skin during close up encounters with dangerous game. As you said however, they did not actually give us that information so all we can do is assume. I look foward to hearing your comments, Jeff Collins | |||
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| <Zingela> |
Why is that this argument comes up time again about the killing power of the 45/70 on DG? I know that a giraffe is not dangerous but it has now been clasified as a pachiderm (spelling) that is a thick skinned animal. I have over the years shot several giraffes with my home loaded rounds from my Marlin 1895SS and achived very good penitration. Shots placed on the shoulder have penetrated the shoulder bone passed through the entire body cavity and almost exited on the offside shoulder. Also through that shoulder bone. The bullet that I use is a 360gr solid based bullet made here in South Africa by Rhino. Kobus v/d Westhuisen can be contacted to verify this and his website is http://www.rhinobullets.co.za I have also had clients shoot our african buffalo with it but using 400 Barnes suoper solids. These have passed straight through on broadside shots. Breaking both shoulders. You see I believe that as our animals here in S.A. have not read the balistic tables, they don't know which calibre or bullet they should go down for or "allow" to kill it. ![[Big Grin]](images/icons/grin.gif){kind=icon} I beleive that we should kill our prey as quickly and as cleanly as possible and therfore I would not allow a client to use anything that I did beleive would do the job. I have had clients botch shots with 460 Weatherbys, shot placements is as always the most important aspect to hunting. I will be hunting a Buffalo in 2 weeks time with a client who will be using a 45/70. I will let you know how this one goes. [ 06-29-2002, 18:54: Message edited by: Rob Duffield ] | ||
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| One of Us |
I am always amazed that people argue good marksmanship when trying to defend use of a light caliber. Good marksmanship should be practiced regardless of what you use. The question is whether the 45-70 is up to (a) penetrating deeply enough when the shot presented is less than optimal, and (b) whether the 45-70 has the stuff needed to stop a fight at very close range. Any caliber works when the shot is perfect. Perfect shots do not test whether a caliber has the right stuff. And the client does not always take a perfect shot or hit exactly where he should. [ 06-29-2002, 19:49: Message edited by: 500grains ] | |||
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| <Norbert> |
jnc91: Excuse my limited english. I said we don�t learn from this study, because a) it is not given all parameters to see what they were doing, b) we already know that on close distances bullets from rifles tend to tumble. On the contrary we can say, that the results prove they must have used too close a distance and therefore the figures of penetration are useless at least for the rifle. Posted above I said, relative penetration of calibers in the same medium under sufficient conditions tells the hunter valuable information. | ||
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| one of us |
Fair enough. | |||
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| one of us |
Originally posted by 500grains: I am always amazed that people argue good marksmanship when trying to defend use of a light caliber. I'm quite sure this has been said of why the 7 Mauser was used to kill elephants. ~~~Suluuq | |||
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