The Down Range Forum
Member Section => Tactical Rifle & Carbine => Topic started by: kilopaparomeo on February 23, 2011, 07:01:53 PM
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Not feelin' so bad about my "ancient" .45-70's anymore ;D
(http://i53.tinypic.com/hu24qq.jpg)
http://www.garrettcartridges.com/penetration.html (http://www.garrettcartridges.com/penetration.html)
PENETRATION: THE 45-70 & 458 MAGNUMS
The following article is based on bullet penetration test results as measured in water-saturated penetration materials (wet newspapers). Water is the primary substance of life, and constitutes about 90% of the content of all mammals. I have observed that some "testers" have chosen wood boards or dry newspapers for penetration testing material, and this is a very poor choice, which in no way simulates the characteristics of a bullet impact with animal flesh. Wood tends to channel the bullet path, and is less demonstrative of the terminal instabilities inherent to non-expanding bullets when impacting game animals, and is thus an inferior material for the testing of bullet penetration characteristics. Water-saturated penetration materials such as newspapers or ballistic gelatin are far superior with regards to their ability to demonstrate the terminal instabilities that typically occur when non-expanding bullets impact live animal flesh. - Randy Garrett
There are few things in the world of ballistics less well understood than the issues relating to comparative penetration. It is commonly believed that the faster one drives a solid bullet, the deeper the penetration. We see this all the time in the various attempts, via new calibers, to achieve higher velocity for improved performance on heavy game. The current rage among big bore shooters seems to be the 458 Lott, since it achieves a good 200-300 fps higher velocity than the 458 Winchester Magnum. It is claimed that the new 458 Lott is an improvement over the 458 Winchester Magnum since its higher velocity supposedly results in more lethal impact-effect and deeper penetration. This, it is claimed, is just the ticket for busting the heaviest game. Of course, the new 458 Lott also achieves greater kinetic energy as a result of its higher velocity, and this is also a convincing characteristic for those brave souls in pursuit of the heaviest game.
Despite all the impressive "science" deployed to reinforce the assertion that higher speed projectiles are more capable of inflicting the deep penetration and impact-effect required to reliably anchor heavy game, one finds that these assertions simply do not withstand common sense, repeatable penetration testing. In fact, if one conducts these tests, one finds that there is nothing that can be observed which supports the assertion that the faster one drives non-expanding solids the deeper they penetrate.
Very interestingly, if one takes the Hornady 500-grain .458 diameter solid bullet and compares the penetration that results from impact speeds varying from about 1500-fps to 2500-fps, one finds that the higher impact speeds produce the least penetration. When driven to about 1500-fps (as the 45-70 will do) one finds that such solids produce nearly 6-feet of penetration in wet newspapers. When the same bullet is driven to about 2100-fps (as is characteristic of the 458 Winchester Magnum) one finds that the penetration is reduced to about 4 to 4 and 1/2 feet. When one tests the same bullet at 2300-2400 fps (as is characteristic of the 458 Lott) one finds that the penetration comes up nearly 20% short of that produced by the 458 Winchester. And when one tests the same bullet at the blistering speeds characteristic of the mighty 460 Weatherby Magnum, one finds that the penetration achieved is the most shallow produced by the various 458s.
What is apparent from testing is that penetration stops increasing at impact speeds above about 1250-1300 fps. When the impact speeds significantly surpass about 1600-fps, there is a very definite and measurable decrease in penetration depth. This raises some interesting issues regarding the relationship between kinetic energy generation and impact-effect. Although higher velocity projectiles always generate more kinetic energy they clearly do not produce deeper penetration, and when the velocities reach the levels common to today's magnums, the increases in velocity result in significantly reduced penetration. Simply stated, the faster they strike the faster they stop.
Fortunately for all of us who shoot the 45-70, it can be considered to be the deepest penetrating of the various 458 calibers. This is not due to any particular inherent superiority, but due to the 45-70's "inability" to achieve the velocity with heavy bullets that leads to decreases in penetration. The reasons why high impact speeds reduce penetration are not well understood. However, anyone who takes the time to run comparative penetration tests will find that those of us who pack a good 45-70 with heavy bullets need not take a back seat to any other 458 caliber, especially when the game is heavy and the penetration requirements are great.
- Randy Garrett
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That is a nice looking rifle.
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I have always thought (JMHO) that the speedsters were really only good for flatter trajectories over longer ranges (shooting mountain goats off the OTHER mountain! ;) ). For stop were they stand power a big slow round does the job better (IMHO). No 'hard science data just common sense.
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So what ? One well placed 458 Lott, 458 Win, or 45/70 will stop an Elephant DRT.
What more can you ask of a bullet ?
But then, so won't a few bursts from the full auto AK's used by many poachers because it's what they have. (personally I'd prefer an RPG )
As a personal comment to KPR it sounds like you've got enough gun for sure, But I don't see any benefit to 4 -6 1/2 FEET of penetration.
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you have to remember, all the energy has to go some where...
It goes to these 3 places.
1 reshaping the target.
2 reshaping the bullet
3 heat.
A+B+C= D
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you have to remember, all the energy has to go some where...
It goes to these 3 places.
1 reshaping the target.
2 reshaping the bullet
3 heat.
A+B+C= D
4. Reshaping your shoulder. ;)
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As a personal comment to KPR it sounds like you've got enough gun for sure, But I don't see any benefit to 4 -6 1/2 FEET of penetration.
Sure, you say that until you encounter one of these in the woods...
(http://www.zmescience.com/wp-content/uploads/2011/01/trex.jpg)
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Sure, you say that until you encounter one of these in the woods...
(http://www.arizonaskiesmeteorites.com/Dinosaur_Fossils_For_Sale/T_rex_fossils_Tyrannosaurus_rex/Tyrannosaurus)
A little red X? ;D
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I see it now with Firefox.
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A little red X? ;D
Fixed it!
Or one of these!
(http://www.homeofrock.de/ArtikelBios/Verschiedenes/Pics/GR/T_Rex_Ride_A_White_Swan.jpg)
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Bang a gong. Get it on.
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Young Elton John on piano.
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Candidate for Thread Drift of the Year Award. Start with big bore penetration end with Elton John. Not what I intended ??? ;D
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"When one tests the same bullet at 2300-2400 fps (as is characteristic of the 458 Lott) one finds that the penetration comes up nearly 20% short of that produced by the 458 Winchester. And when one tests the same bullet at the blistering speeds characteristic of the mighty 460 Weatherby Magnum, one finds that the penetration achieved is the most shallow produced by the various 458s."
This is not a universal result. It greatly depends on the bullet. For example when Speer was producing their Tungsten Carbide Core African Grand Slam Bullets they advertised 60" of penetration, (5 FEET), in pine with the .460 Weatherby Magnum. When you get energy levels that high with a properly constructed bullet, it takes a lot to stop it. Look at AP bullets in the .50 BMG cartridge. It's amazing what they will get through. Bill T.
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Thank you Bill for bringing us back from the brink.
True statement as they were only looking at a single bullet type, the 500 gr Hornady solid. What would be a more conclusive study is to look at a range of bullets at a range of velocities and use that to see if there is a correlation to be drawn from velocities.
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Thank you Bill for bringing us back from the brink.
True statement as they were only looking at a single bullet type, the 500 gr Hornady solid. What would be a more conclusive study is to look at a range of bullets at a range of velocities and use that to see if there is a correlation to be drawn from velocities.
Don't blame us it was your picture. ;D
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Candidate for Thread Drift of the Year Award. Start with big bore penetration end with Elton John. Not what I intended ??? ;D
There is a joke in there somewhere but I'm not going to be the one to drag it out. ::)
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But isn't the .577 specifically designed for T-Rex?
All aside, I agree that the velocity issues are all about the LINE from the muzzle TO THE target.
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no, the 577 was a nitro express to start out with. strait walled and rimmed.
the 577 t rex was made by A square in the 90s( I want to say 92 or 93) its a bottle neck rimless
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Another thread was posted about Hemingway's .577NE Westley Richards double rifle coming up for auction.
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Another thread was posted about Hemingway's .577NE Westley Richards double rifle coming up for auction.
I know, I started it ;D
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Here's a thought. It depends on the charateristics of the TARGET as much as the cartridge. I saw an episode of Myth Busters once. They were looking at armoring a car using phone books. Long story short. Two phone books INSIDE the windshield would stop a .308. The same two OUTSIDE? Not so much. IF the bullet was damaged by hitting something hard, like thick grizzly bone, its impact evaporated. If it hit something soft, like tissue first, it would still penetrate the soft parts. Lesson? For an animal where you have to go through flesh to hit bone, you need a different load than on one where you need to go through bone to damage flesh. FWIW.
FQ13
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For an animal where you have to go through flesh to hit bone, you need a different load than on one where you need to go through bone to damage flesh. FWIW.
FQ13
Maybe that's why we don't hunt stuff with exoskeletons. ;D
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Maybe that's why we don't hunt stuff with exoskeletons. ;D
Like say, vehichles. ;) Seriously though, there is a difference between say a bear and a moose as far as how they are built. The moose will have less hair and tissue between the the skin and the bone that you need to break to hit the important stuff. The bear is a much denser proposition, requiring more hair and tissue penetration before you hit bone and then get to the internal organs. Just a thought.
FQ13
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Pl;ease to keep in mind that my comments apply to my quarter of MAINE.
Bear? Moose? NEITHER of which, at reasonable distances, (<200 m), will stand up to a well placed shot of a full sized MBR...or just about ANY shot from a .577, regardless of letters...
Don't be silly...I'm not talking HOOF or PAW, here...
From 200-400, it helps to be VERY good and VERY rehearsed as well as VERY sighted in!
At 400+, you'd have to be damn hungry, as well.
There are guys out there, heck, even ON this BOARD, that can make "that shot" with a .223. Or a .22 Mag. But, are YOU willing to BET your LIFE that you are THAT guy?
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But isn't the .577 specifically designed for T-Rex?
The .577 bore diameter was originally designed in the Snider round. A early black powder African cartridge. The late Elgin Gates tested it a lot in the 70's and found it to be a formidable African weapon even by modern standards. When you start tossing golf ball sized chunks of lead things tend to die fast. Bill T.
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The .577 bore diameter was originally designed in the Snider round. A early black powder African cartridge. The late Elgin Gates tested it a lot in the 70's and found it to be a formidable African weapon even by modern standards. When you start tossing golf ball sized chunks of lead things tend to die fast. Bill T.
Psst....Bil....I KNOW! I was being a little bit....facetious...It happens after watching all those YouTube vids of people shooting the T-Rex.