Penetration: .45-70, or .458 Win Mag?

[peacemaker45]

Ok, I know how reliable information in glossy gun-rags usually is, but I think the phenomenon may have reached a new depth.

John Taffin, in the 2009 Special Edition of GUNS, wrote an article about the .45-70, singing it's praises. While I'm as much a fan of the .45-70 as anyone, he did make one statement that seems to defy the laws of physics. He said that the .45-70, using a 500 grn bullet, at 1,500 fps will out penetrate a .458 Win Mag, using a 500 grn bullet, at 2,100 fps. Using a test medium of wet newspaper, the .458 penetrated 4.5 feet, and the .45-70 six feet.

This doesn't seem to make sense. Only thing I can figure is that the test was rigged, and he's very carefully not saying so. He did not say that the two guns used the same 500 grainer.

Any info, data, or opinions?

 

[rcmodel]

It does makes perfect sense if he was using expanding bullets in both rifles, or an expanding bullet in the .458 and a hard-cast lead bullet in the 45-70.

The higher velocity of the .458 would mushroom a soft-point bullet much quicker & bigger then the 45-70. Once the bullet expands, its like throwing out a drag parachute.
The more it expands, the bigger the parachute.

And Hard-Cast flat point lead 45-70 bullets don't expand at all, and will shoot through a big big animal lengthwise.

If you used that same bullet in the .458, it would do even better.

rcmodel

 

[Tarvis]

Logic tells us that the same bullet would penetrate the same distance. Sound like he used factory ammo for both, the 45-70 being a hard cast bullet and the .458 winmag something different. Call him up and tell him he's an idiot.

Edit: rcmodel had a good point; if a bullet was going slow enough to not expand as normal, it would penetrate deeper. Kind of like the lethality range of 5.56 ball ammo, in the sense that 5.56 will split at the canneluer when it's above a certain velocity, which is like 150 yards in a 20" bbl and 50 yards in a 16".

 

[rcmodel]

But, the same bullet will not penetrate the same distance.

An expanding bullet will expand more & sooner at .458 velocity then at 45-70 velocity.
So it probably wouldn't penetrate as far.

A hard-cast bullet that doesn't expand would penetrate further from the .458 because it is going faster then the 45-70.

rcmodel

 

[Dr. Tad Hussein Winslow]

It depends upon the bullet. If it's an expanding bullet then he's right. The slower velocity means less expansion, means more penetration.

OTOH, if were talking a tungsten solid, then no, the opposite is true. The .458 winmag will penetrate much further.

Bullet construction as matched with vel. is so very important.

 

[kcmarine]

Box O' Truth article on .45-70

Eh. Probably doesn't answer any questions. But I've always wanted to post that.

The other posters are probably right. A higher speed expanding bullet is going to expend its energy into the target faster and over less distance than a FMJ or hard cast bullet. A good test to see if he was BSing would be to compare the impact energies. If the .45-70 was significantly lower, then we would have quite a physics problem on our hands.

Also, when I originally went to that page that's in the link, there was a weight loss patch ad and Lane Bryant on the same page. Personally, I find that hilarious. Just wanted to get that out there.

 

[rcmodel]

If the .45-70 was significantly lower, then we would have quite a physics problem on our hands.

I don't find that to be a problem at all.

A 240 hard-cast .44 Mag handgun load will shoot through an elk at 100 yards, with less then 1,650 ft/lb of remaining energy at that range.

A 125 grain 30-06 varmint load has twice as much remaining energy at 100 yards, but it sure won't shoot through an elk!

Penetration all depends on the Sectional Density of the bullet, and whether or not it expands.

rcmodel

 

[jmr40]

Not surprising at all and is common with all calibers. Under the right conditions a 30-30 will out penetrate a 30-06 and so on. Also it is not unusual to see bullets penetrate better at longer ranges after they have slowed down.

Several years ago the Alsska Game Dept tested many guns to see which would be best to arm officers with to stop bear attacks. At 15 yards they determined the 30-06 out penetrated the 300 win mag.

That does not however mean that I think a 45-70 is superior to a .458. There are other factors that come into play.

 

[Acera]

But at the end of the day, which round would you rather have when facing a pissed off cape buffalo?


I'll stick to my Styer in .458 Win Mag.

 

[Stevie-Ray]

But at the end of the day, which round would you rather have when facing a pissed off cape buffalo?

20mm or so