45/70 for large bear... ammo?

Dean2

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Load a 400 grain bullet at 1400 FPS. Maximum penetration, quick recovery. Most 500 grain bullets will not feed properly in a Marlin lever action. You can load a 400 grain bullet all the way up to 1900 fps but it will NOT kill faster or better. All it will do is beat you up and slow down second shot recovery. Practice snap shooting three rounds as fast as you can fire them at 30 yards. If you can use a moving target so much the better. Keep at it until you can get 3 accurate shots off in under 3 seconds. Practice is far more important that any other consideration, as is staying calm when being charged.

This is by Randy Garret of Garret Ammunition Manufacturers.
https://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
 

Mrvmax

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Load a 400 grain bullet at 1400 FPS. Maximum penetration, quick recovery. Most 500 grain bullets will not feed properly in a Marlin lever action.
So have you had any issues chambering 550 grain bullets in a Marlin? When I was researching loads for my 1895 SBL I did not run across anyone having feed issues with the JB Young 550 Crater. I had zero feed issues so I am wondering if things have changed in production rifles.
 

Dean2

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So have you had any issues chambering 550 grain bullets in a Marlin? When I was researching loads for my 1895 SBL I did not run across anyone having feed issues with the JB Young 550 Crater. I had zero feed issues so I am wondering if things have changed in production rifles.
I tried 500 grain Hornady RN and solids. Both need to be crimped and if loaded at the cannaleure they are too long. Hodgdon doesn't list a load over 400 grains for the Marlins/Levers but I know there are lots of places making them. If you had a second cannaleure and could seat the bullets much deeper you can probably get them to work but you would need to make sure you used the right powder so you have enough room.
 

Murph1951

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Using a 45/70 for large(?) bear would be ok for a very experienced guide and a **** good shot. When fishing Alaska I would always have my 30-06 loaded up with 220 grain Woodleigh Weldcore bullets. As I aged I started bringing my Remington 6oo in 350 magnum with 250 grain bullets. I was lucky because I never had to shoot a bear, came close a couple of times. These bears are not big, they are freakin' huge. I still felt undergunned when one would come close. Also no scope on either gun because if trouble happens it will be up close and very, very personal.
 

odoylerules

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I like the suggestion of the Hammers. It has have pedals that frag off and cause wider damage and the main core stays intact and penetrates deeply
 

Varmint Hunter

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The 402gr Hammer that I used was probably the first time it was used in a 45-70 for hunting. Muzzle velocity from my 18.5" Marlin bbl was 1,700 ft/sec. The bullet petals shear off at an angle and leave aprox 90% of the flat faced bullet shank to keep moving forward.

It would be interesting to see exactly how much penetration you would get. My outfitter bet me that the bull would stop/catch that bullet. He lost. :>)
 

del2les

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Many years ago, I used a 45-70 with home hard cast 500gr (actual 490gr with wheel weights then water quenched) and a couple of lighter solids, in a converted Mauser action and loaded to +P vels for dangerous game and other hunting, and they performed very well. Actually, I never saw much difference between it and the 458's other were killing with.
 

Varmint Hunter

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I had very little luck, accuracy wise, with hardcast lead bullets in my 1895SBL (JM). That is why I have concentrated on jacketed bullets and mono-metal bullets. The 350gr Swift A-Frame bullet has shot into .5"-.6" @ 100 yds on several occasions.

However, for the OPs needs, accuracy is fairly irrelevant.

With regard to the Garrett penetration information; it merely deals with penetration as a single component of terminal performance and does not address the speed of incapacitation. I believe that higher speed impacts set bodily fluids in motion and produce a shock wave through the body which accelerates incapacitation, sometimes significantly. Roy Weatherby was definitely onto something. So while a slower 45-70 bullet might penetrate deeper, a faster bullet of the same heavy construction might incapacitate faster.

That's just my 2 cents.
 

gsteve

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Sep 23, 2015
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Montana or Wyo? Guided or on your own?

I take it this is the gun you plan to carry daily in the field for elk?
Its in BC , guided elk trip. Ill be using a 340 wby on elk. If i get and elk i want to keep wandering around with my 2 buddies as they hunt. The 4570 would be for that.
 

Son of a Gun!

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I've developed a load for my 1886 Win. Replica that I plan to use for a big bull Bison! I killed a bull moose with it 3 years ago and would not hesitate to use it on a big bear! It consists of the Swift 350 gr. A-Frame pushed with 57 grs. of 3031 to right at 2000 fps.
 

Lycanit

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Nov 6, 2015
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I am dubious as to the veracity of statements regarding none expanding projectiles and relativistic velocity and it's effects on penetration. Disruptive effect on the presentation portion of the projectile certainly will cause a loss of depth however saying a none tumbling, none expanding projectile looses penetration due to velocity alone is false. Why would the military develop sabot rounds for the Abraham tank? It's the same concept. I will agree completely that double the velocity does not in any way guarantee a specific increase in depth of penetration. Nor does 300 fps increase reduce your depth by any margin, unless your material of testing is inconsistent and there in lies a probable truth. Then again, what do I know. I'm just old.
 

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