458 RUM

12 March 2003, 15:21

Guy Morrison

458 RUM

Has anyone got any ideas on how practical this wildcat would be? I would building it in a new LH Montana long action. I am interested in shooting both cast and jacketed bullets in their respective velocity ranges. Guy

[ 03-12-2003, 06:28: Message edited by: Guy Morrison ]

12 March 2003, 15:40

Robgunbuilder

Welcome to the forum! I suspect the 458 Rum also known as the 460 G&A will perform somewhere between the 458LOTT and the 460 WBY. It would be a easy gunsmithing project, but remember that anything over 2400fps with a 500 gr bullet may be in fact detrimental. Most folks agree that for hunting the 460WBY needs to be loaded down to 2400fps. I suspect that the 458RUM/460G&A will hit 2400fps a bit more easily and at lower pressures than the LOTT. It's not a bad project IMHO.-Rob

12 March 2003, 18:30

snowcat

Is higher velocity detimental to performance due to very specific bullet design parameters??? Confused as to why more power could hurt you if the bullet stayed together (think a monolithic solid.) Just curious.

13 March 2003, 04:24

HunterJim

Snowcat,

Two effects of too much velocity have been reported: lower penetration and recoil interfering with a follow-up shot.

It seems that a .458"/500 grain solid at around 2,350 fps yields the most penetration with lower or higher velocity showing less.

Weatherby cartridges on the .378 WM case are too much of a good thing.

jim dodd

13 March 2003, 04:31

500grains

I wonder if there is a little bit of apples and oranges here. The 460 wby mags often have a slower twist than custom 458 lotts, and the faster twist tends to increase penetration. So in part the lesser penetration of 460 wby rifle may be attributable to their slower twist rate.

I do not understand the physics of why a bullet that holds together at 2700 fps would penetrate less than the same bullet at 2300 fps, but numerous field reports indicate that is indeed the case.

13 March 2003, 05:30

John Ricks

I have read some discussion of 500 gr. bullets at 2600 to 2700 ft tend to glance aroound bone instead of through, maybe some has experience with this? I am sure it depends on bullet construction also, and this info comes before the days of present bullets, Super Penetrators, etc. Maybe Norbet has some experience?

The A-Square manual has a discussion on twist vs. penetration.

In my shooting of 458 Win, 458 Lott, 450 Dakota and 460 Weatherby rifles I have noticede a well built Lott, designed both for recoil management and sight picture with iron sights, is a preferred rifle to shoot, comfort wise. However I really like the 500 Jeffery, the recoil seems to be much different to me than a 460 Weatherby.

I think a 460 G&A or 458 Ultra, running at about 2350 to 2400 with 500's, would be a nice rifle to shoot and would have all the performance one needs at less pressure than the Lott.

There was considerable discussion last year on this board about the 460 G&A and techniques of case forming, reloading, etc, used for realiable headspacing of the cartridge.

[ 03-12-2003, 21:39: Message edited by: John Ricks ]

13 March 2003, 05:48

Brent

quote:
Originally posted by 500grains:
I do not understand the physics of why a bullet that holds together at 2700 fps would penetrate less than the same bullet at 2300 fps, but numerous field reports indicate that is indeed the case.

And thus the .45-70 DGR?????

Brent

13 March 2003, 06:58

Brent

quote:
Originally posted by 500grains:
I do not understand the physics of why a bullet that holds together at 2700 fps would penetrate less than the same bullet at 2300 fps, but numerous field reports indicate that is indeed the case.

And thus the .45-70 DGR?????

Brent

13 March 2003, 15:48

InfoSponge

quote:
Originally posted by 500grains:
I do not understand the physics of why a bullet that holds together at 2700 fps would penetrate less than the same bullet at 2300 fps, but numerous field reports indicate that is indeed the case.

Maybe I can help answer part of the physics question. A deforming bullet (i.e., not a hard solid) will penetrate less at high velocities. I won't attempt to explain the very complicated mechanics involved. Indeed, they are simply not easily explained, and must be estimated with complex computer simulations in order to get a reasonably accurate analytical solution. This is the kind of thing that is done by the Aberdeen Proving Ground when the Army is testing tank projectiles, but such analysis is rare to unheard of when it comes to hunting bullets.

However, it is still possible to understand the basic conclusions, even if you can't do anything more than trust the empirical and analytical efforts that went into arriving at those conclusions. A deforming bullet has a certain amount of energy available when it impacts on a target. That energy will be spent in essentially three ways: 1) bullet deformation; 2) temporary/elastic target deformation; 3) permanent target deformation. The last of these, permanent target deformation, is what determines the hole left by the bullet's passage and the depth of penetration. Hunting bullet energy spent on 1) and 2) is essentially wasted, since it has little to no dependable effect on wounding or killing of game. Permanent deformation occurs in two phases: 1) that which occurs while the bullet is travelling fast enough so that the dynamic pressures on the bullet are sufficient to cause it to flow and deform; 2) that which occurs after the bullet has slowed sufficiently so that it has essentially stopped deforming. Permanent deformation of type 2) is all but identical for all bullet impact velocities: it doesn't begin until the bullet has slowed to the same velocity, regardless of initial velocity. However, with higher velocity bullet impacts, type 1) permanent target deformation occurs much more quickly and over a shorter distance as the impact velocity exceeds a certain threshold value (which depends in large part on bullet type and construction.) With high velocity impacts on game, more of the bullet's energy goes into temporary/elastic target deformation (essentially a hydrodynamic splash effect) and into bullet deformation. Furthermore, the deformation of the bullet itself occurs much more quickly, thus limiting the distance the bullet can travel while generating type 1) permanent target deformation. So, the sum of the velocity independent type 2) permanent deformation and reduced type 1) permanent deformation is less than if the bullet were to impact at the lower, optimal velocity.

Phew! Hope that helps.

As for why a hard solid should penetrate less at higher velocities, I'm not sure. The only evidence that I am aware of shows flat fronted, large meplat bullets increasing penetration with increased velocity. I would expect that to be true of round nosed hard solids as well, except for the difference in bullet stability within the target animal. If round nosed solids do indeed penetrate less at higher velocities, I would expect that it is because they become unstable and tumble. If that were the case, then a higher twist rate for the same impact velocity would likely show somewhat increased penetration.

I'd be very much interested in seeing good data on decreased round nosed hard solid penetration with increased velocity over a certain threshold value.

14 March 2003, 08:35

Guy Morrison

Gentlemen
Thank you for your input
Guy

15 March 2003, 13:48

hammerhodder

I believe it is called the splash effect or something similar to that.You can push your hand thru water with a slowpunch,but try to do it fast.An animals body is similar in composition to water.I m no physics expert,but that is my elementary answer to your question.

15 March 2003, 13:52

hammerhodder

Heard of an experiment where a slow moving bullet and a fast moving bullet were fired at a jug of water.The slow moving bullet penetrated the jug were as the fast moving bullet exploded the jug,not penetrating.It released it s energy fast and violently.I have never tried this but I believed the source.

17 March 2003, 12:20

Socrates

Head spacing without a belt, on a wildcat big bore, can, as some of the 404 fans know, can be baffling, and you can spend a lot of time with your gunsmith.

Why not just use the 460 weatherby, and load it down?

Problem with the Lott is to get the magic 2400 with 500 grain bullet requires a long barrel, and high pressure...

However, you do get to carry a lot more of em if you use a Brno, or CZ magnum action...
and, if you reload, the Lott is cheaper to reload, using less powder..
S

19 March 2003, 16:50

Roger

Topic: American Bison and 45-70
VincentR
Member posted 03-16-2003 05:13 PM
--------------------------------------------------------------------------------
Cape Buff
For me the 540gr and 420gr Garrett Cartridges Hammerheads have proven to be "absolutely lethal" to everything I have used them on. They have, in my opinion, made the 45-70 caliber and in particular, the Marlin lever rifle, a true killer to anything on the face of this planet! The idea is to breakdown the skeletal frame of the animal with a shoulder broadside shot whenever possible and using a second shot only if necessary or required. The broadside shot will completly exit (in my case the sole exception being Elephant and Rhino) the far side. It is to me, a matter of "what animal and about how far the shot". In my opinion, the 540gr Garrett Cartridge Hamerhead is absolute "DEATH" to "ANY" animal within 100 to 150 yards. I site as my personal examples the following animals I have taken with the 540gr Hammerhead: Elephant, Rhino, Cape Buffalo, Hippo, and American Bison. As for the 420gr Hammerhead, well I have used it with extremely gratifying results (total devastation) out to 225/235 yards on Lion, Leopard, Serval, 4 Warthog, 3 Kudu, 2 Oryx, 2 Waterbuck, Nyala, Bushbuck, 3 Zebra, 2 Blue Weldebeast, Black Weldebeast, Baboon, 3 Common Blesbuck, White Blesbuck, 4 Common Springbuck, Black Springbuck, Common and Mountain Reedbuck, Jackel, Livingston Eland, REd Hertabeast, Whitetail Deer, Hogs, Mouflon Sheep and many many other animals.
I have an extensive collection of rifles including: 458 Win Mag, 416 Rigby, 375 Super Mashburn and about a dozen or so others. BUT the rifle I have come to use the MOST is my lever action Marlin 45-70 loaded with Garrett Cartridges 540gr or 420gr Hammerheads.
------------------
VINCE
NRA Member
NAHC Life Member
NRA Cert. Firearms Inst.
SCI Member
Wyoming Wildelife Fed.
SCI African D.G. Big Six

Gents,

Check the list of animals taken by Mr. Lupo. Doesn't take a rocket scientist to figure out the effectiveness of a heavy, slow, and flat bullet to take game animals.

He has also mentinoned that if he should win the Searcy Double Raffle, he is going to have it chambered for the 45/70. Mucho balls Vince, I like your style.

Roger QSL

20 March 2003, 03:12

<RussT>

Fred Zeglin at Z-hat does this one and has the dies, load info etc.. Try: http://z-hat.com/Ultracat.htm