The Cartridge .458 Lott or .450 Watts and .450 Ackley Magnum

Norbert Hansen

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The Cartridge .458 Lott or .450 Watts and .450 Ackley Magnum

This cartridge is a very good compromise between killing power, usability and availability of rifles and components. Its is a perfect cartridge for hunting all species in Africa from elephant to plains game as small as duiker. For this range of use you only need two loads. Many professional hunters are relying on this caliber. Some manufacturers are now offering factory loads and also factory rifles are on the market.

Properties and advantages
-With modern high energy powders a 500 gr bullet can propelled up to 2400 f/s, the "magic" velocity for best bullet performance on big game. The resulting muzzle energy is 8600 Joule, for comparison: .460 Weatherby: 9800, .500 Jeffery: 9300, .458 WinMag: 6300. The Penetration Index of the .458 Lott amounts to 132 and ranks in the upper class together with cartridges like the .416 Rigby and better than a .470 NE.

-The supply of belted cases and .458 diameter bullets is plenty compared to other big game cartridges. New on the market are Hornady factory loads and properly head stamped brass as well.

-It is very easy to convert rifles, esp. .458 WinMag to this caliber. Because there is no standardization, Lott and Watts are often mixed up. Modern reamers for the Lott are with a case length 2.850". Another improvement of the Lott concept is the forming of a "ghost shoulder" providing a parallel neck. The resulting OAL of 3.650" fits in magazines of most rifles used for conversion. The magazine capacity keeps the same and is usually 3 to 4 rounds and more than with the bigger cases. The Lott is the most powerful cartridge based on the case head diameter of the H&H belted case.

-With 400 gr bullets you can develop loads for plains game, which show a flat bullet path and a point blank range up to 225 yards. With a good readjustable scope the rifle is appropriate for the "one rifle safari"!

-With a good recoil pad the rifle´s recoil is manageable and the weight still below 10 pounds, so you can walk with it for hours in the heat of Africa.

-In emergency, you can use .458 WinMag cartridges and a lot of safari camps in Africa have some Lott ammo kicking around.

The SuperPenetrator bullet
The SuperPenetrator uses the supercavitation effect and is constructed with a cavitator disk at its nose. It can designed to an optimum of penetration and energy dissipation.

Penetration is a very complicated matter and test results are highly dependent on the methodology and and the test medium used. The only value of artificial target media such as wood, wet paper, gelatine and others is to compare one bullet to another in that particular medium. Plywood and shooting into baffle boxes has little bearing on penetration in animals.

From the field and test experiments we observed two different mechanisms of penetration in animals:
1. The penetration in aqueous tissue; limited by the stability of the bullet’s travel in a supercavitation bubble; and
2. The penetration in bone, hide and sinews; limited by the forces acting on the bullet, (friction, shear resistance, viscosity).

Penetration in big game is often limited by the stability of the supercavitation bubble and unexpected bullet paths as reported often in big animals is due to this effect.

The supercavitation itself is not primarily responsible for more or less penetration. It only keeps the rotational stabilization going on, without supercayitation it would stop by friction. When the bubble collapses, the unstable bullet normally will veer off, in my terms penetration has stopped. By chance the bullet may go a bit further, it is not exactly predictable. There is no non cavitating bullet, but different bullet design shows different duration of the cavitation bubble. The Kynoch profile shows about 70 cm stable penetration, the SuperPenetrator, optimized for animal tissue, about 250 - 300 cm. You don´t need this extreme penetration under normal hunting conditions, but it shows very stable penetration in game and no deviation, tumbling, bending or fishtailing and a up to fourfold penetration length in animals. The research on stable penetration of hunting bullets was not done with the intention to introduce new bullets on the market. It was done just for a discussion with ballisticians, who claimed the impossibility of straight line penetration with RN bullets.

Exterior Ballistics for .458 Lott impr. .450 Watts and .450 Ackley

for comparision .458 WinMag und .460 Weatherby

flug.jpg


Trajectory for .458 Lott impr.

ball458.jpg


lower curve: 500 gr Round Nose 2400 f/s
upper curve: 400 gr Spitzer 2545 f/s

Image below, cartridge .458 Lott and three bullets Woodleigh 500 gr FMJ recovered from frontal head shots on elephant.

cartridg.jpg


This loads with an appropiate scope are an ideal combination for all game in africa from baboon to elephant!
 
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5E0C3F4F-8BC6-4598-A04D-9DA623FE0B91.png
When I googled .458 Ackley improved this thread came up.
I had not heard of of previously and my general understanding was Ackley improved was applied to various bottleneck cases with some exceeding others in various results of various calibre’s
 

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The Cartridge .458 Lott or .450 Watts and .450 Ackley Magnum

This cartridge is a very good compromise between killing power, usability and availability of rifles and components. Its is a perfect cartridge for hunting all species in Africa from elephant to plains game as small as duiker. For this range of use you only need two loads. Many professional hunters are relying on this caliber. Some manufacturers are now offering factory loads and also factory rifles are on the market.

Properties and advantages
-With modern high energy powders a 500 gr bullet can propelled up to 2400 f/s, the "magic" velocity for best bullet performance on big game. The resulting muzzle energy is 8600 Joule, for comparison: .460 Weatherby: 9800, .500 Jeffery: 9300, .458 WinMag: 6300. The Penetration Index of the .458 Lott amounts to 132 and ranks in the upper class together with cartridges like the .416 Rigby and better than a .470 NE.

-The supply of belted cases and .458 diameter bullets is plenty compared to other big game cartridges. New on the market are Hornady factory loads and properly head stamped brass as well.

-It is very easy to convert rifles, esp. .458 WinMag to this caliber. Because there is no standardization, Lott and Watts are often mixed up. Modern reamers for the Lott are with a case length 2.850". Another improvement of the Lott concept is the forming of a "ghost shoulder" providing a parallel neck. The resulting OAL of 3.650" fits in magazines of most rifles used for conversion. The magazine capacity keeps the same and is usually 3 to 4 rounds and more than with the bigger cases. The Lott is the most powerful cartridge based on the case head diameter of the H&H belted case.

-With 400 gr bullets you can develop loads for plains game, which show a flat bullet path and a point blank range up to 225 yards. With a good readjustable scope the rifle is appropriate for the "one rifle safari"!

-With a good recoil pad the rifle´s recoil is manageable and the weight still below 10 pounds, so you can walk with it for hours in the heat of Africa.

-In emergency, you can use .458 WinMag cartridges and a lot of safari camps in Africa have some Lott ammo kicking around.

The SuperPenetrator bullet
The SuperPenetrator uses the supercavitation effect and is constructed with a cavitator disk at its nose. It can designed to an optimum of penetration and energy dissipation.

Penetration is a very complicated matter and test results are highly dependent on the methodology and and the test medium used. The only value of artificial target media such as wood, wet paper, gelatine and others is to compare one bullet to another in that particular medium. Plywood and shooting into baffle boxes has little bearing on penetration in animals.

From the field and test experiments we observed two different mechanisms of penetration in animals:
1. The penetration in aqueous tissue; limited by the stability of the bullet’s travel in a supercavitation bubble; and
2. The penetration in bone, hide and sinews; limited by the forces acting on the bullet, (friction, shear resistance, viscosity).

Penetration in big game is often limited by the stability of the supercavitation bubble and unexpected bullet paths as reported often in big animals is due to this effect.

The supercavitation itself is not primarily responsible for more or less penetration. It only keeps the rotational stabilization going on, without supercayitation it would stop by friction. When the bubble collapses, the unstable bullet normally will veer off, in my terms penetration has stopped. By chance the bullet may go a bit further, it is not exactly predictable. There is no non cavitating bullet, but different bullet design shows different duration of the cavitation bubble. The Kynoch profile shows about 70 cm stable penetration, the SuperPenetrator, optimized for animal tissue, about 250 - 300 cm. You don´t need this extreme penetration under normal hunting conditions, but it shows very stable penetration in game and no deviation, tumbling, bending or fishtailing and a up to fourfold penetration length in animals. The research on stable penetration of hunting bullets was not done with the intention to introduce new bullets on the market. It was done just for a discussion with ballisticians, who claimed the impossibility of straight line penetration with RN bullets.

Exterior Ballistics for .458 Lott impr. .450 Watts and .450 Ackley

for comparision .458 WinMag und .460 Weatherby

flug.jpg


Trajectory for .458 Lott impr.

ball458.jpg


lower curve: 500 gr Round Nose 2400 f/s
upper curve: 400 gr Spitzer 2545 f/s

Image below, cartridge .458 Lott and three bullets Woodleigh 500 gr FMJ recovered from frontal head shots on elephant.

cartridg.jpg


This loads with an appropiate scope are an ideal combination for all game in africa from baboon to elephant!
Yes. But so is a 300 gr .375, with a whole lot less fuss, bother, carry weight and recoil.
 

fourfive8

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Thanks for posting! Good report there Norbert Hansen- well written. I have done some testing of a couple of different med to large bore bullets into tough test media where the impact velocity was equivalent to an average DG distance shot that started at the muzzle @ 2400 fps. There is most assuredly something to the compression (cavitation) bubble theory of stabilization and concurrent deep, straight line penetration in denser-than-air media. While my sample universe is relatively small it certainly points to the validity of the theory. Of those tested, the bullet that impressed (and surprised) me the most in terms of total depth straight line penetration was the .458 450 gr Flat Nose, turned copper monolithic made by GS Custom. The cartridge used for these tests was a 450 Watts.
 

One Day...

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I agree with Red Leg. If the argument is "good compromise between killing power, usability and availability of rifles and components. Its is a perfect cartridge for hunting all species in Africa from elephant to plains game as small as duiker," I will say from experience (I own .375 H&H, 416 Rigby, .458 Lott) that the .458 Lott recoil exceeds what most shooters are comfortable shooting casually, day in, day out, on a mixed bag hunt.

A 9 lbs .375 H&H rifle launching a 300 gr bullet at 2,530 fps produces 37 ft/lbs or recoil at 16 fps. A 10 lbs .458 Lott launching at 500 gr bullet at 2,300 fps produces 70 ft/lbs or recoil at 21 fps. Recoil is a less (55 ft/lbs) with a 400 gr bullet - it is lighter but it flies faster, the two factors influence recoil in opposite ways - but both sectional density and ballistic coefficients drop significantly.

With twice the recoil of a .375 H&H, all but the most experienced shooters will be much better served by a .375 H&H than by a .458 Lott on a mixed bag hunt.
 
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CBH Australia

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I had a .458wm considered having it rechamber to a Lott, Kudu services in Melbourne seems to be a recommended for big bore stuff. Dealer to dealer transfers etc the cost goes on and im nowhere near any DG st present.
I sold it to fund the .375H&H wanting the Classic cartridge.
The .458Ai shown is listed on usedguns.com.au by a dealer. I expect they have the details correct.
Anyone know much on the 458AI version?
That other website is the other place where dream lose time and procrastinate the things i should be doing.
Presumably the Lott is the common upgrade or variant but the historically noted .458wm faults were ironed out long ago.
Where is @Badboymelvin he likes the .458wm seems to use it on everything.
 

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I have no experience with the 450 Ackley but according to Carts of the World, it is very similar to the Lott and Watts except it does have a small shoulder. The design downside, IMO, to this is that all three, the Lott, the Watts and the Ackley all use the same basic parent belted cartridge (a blown out 375 HH) meaning that a real shoulder, however small, will reduce the body taper of the cartridge even more than for the Lott or Watts. IMO, body taper is important for positive extraction and less important for smooth chambering (the most common case made for the attributes of the 375 HH which does have quite a bit of taper). The only time more taper is really needed for smooth chambering is if the action is not "tuned" or designed correctly for a particular round to begin with. The other design downside of the Ackley version is that the small shoulder and slightly larger upper body diameter actually prevents the use of 458 WM ammo in a pinch. There is simply too much lateral clearance for forward body support for the WM which would lead to unacceptable accuracy at least and ruptured cases at worst.

Here are the critical cartridge specs for the 450 Ackley as provided by Carts of the World. Neck length or body length would be important numbers to get a full picture for the design but are not provided.
Standard specs for regular belted mag based on 375 HH.
Shoulder Diameter- .503
Case length- 2.885
Crtg length- 3.665
 

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With twice the recoil of a .375 H&H, all but the most experienced shooters will be much better served by a .375 H&H than by a .458 Lott on a mixed bag hunt.

I don't know. I think with the proper fit rifle anyone can shoot a big bore. This 125 lbs guy in the picture uses a .500 MDM with a 20" barrel (same as my elephant rifle) with a slightly reduced load that pushes a 500 grain bullet at 2,250 fps (full load is 2,370 fps). It uses 92 grains of IMR 8208 and putting it into a recoil calc for a 9.5 lbs rifle gives 82 ft/lbs of recoil. He had shot 25+ elephants with it 6-7 years ago and probably a lot more since then. He was looking for a 100 pounder, and came close at 90 though by this time he might have found it.

666_500_csupload_65836545.jpg


Edit: Also, I don't think anyone without much experience is going to take a big bore to hunt DG in Africa either. I think most of the inexperienced shooters are the ones taking the cheap hunts for the first time in RSA. They will have as much trouble (if they do) with a .375 H&H as they would with a .458 Lott.
 

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Badboymelvin

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I had a .458wm considered having it rechamber to a Lott, Kudu services in Melbourne seems to be a recommended for big bore stuff. Dealer to dealer transfers etc the cost goes on and im nowhere near any DG st present.
I sold it to fund the .375H&H wanting the Classic cartridge.
The .458Ai shown is listed on usedguns.com.au by a dealer. I expect they have the details correct.
Anyone know much on the 458AI version?
That other website is the other place where dream lose time and procrastinate the things i should be doing.
Presumably the Lott is the common upgrade or variant but the historically noted .458wm faults were ironed out long ago.
Where is @Badboymelvin he likes the .458wm seems to use it on everything.

Hey mate,

You wouldn't have gone wrong with Bob at Kudu Services - he does great work. He's done a .375Wby for me and a custom .458WM for me as well... which I really shouldn't have sold...:cry:

You're right, I love the .458WM! Have owned 5 and just on Saturday dropped a nice Red Deer with my Zastava (y)

You're also right about the problems being ironed out with it a long time ago. I'm shooting OLD factory ammo from Winchester (probably '80's vintage) and not only does it still go bang it still reaches factory claimed velocity.

I have been reloading for the .458 for years now and I've never had a problem getting 2150fps with a 480-500gn bullet. All in the summer-time of Australia too.
I'm currently working on a 550gn load that should reach 2100fps... and I'm no reloading super-expert - I'm a nurse on a surgical ward!
If I can do it safely - why can't anyone else? I think that shows that a lot of the drama's that dogged the .458 are a thing of the past.

I don't tend to get into arguments now about the .458... been there, done that. People have the right to believe what they want and use what they want.

The .458Lott, .458AI and the like are all great... but not for me.
The recoil of the .458WM with the loads I mentioned above are my absolute limit - and after corresponding with many, many PH's, gun writers, hunters, bullet manufactures and cullers they all say the same thing, the loads mentioned above are absolutely suitable for DG.
If you can handle more - great! Go for it! But if not, you're still OK. History has proved that over and over again...

Cheers,

Russ
 

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I’m a huge fan of the Lott. The difference in effect on a buff vs my .375 is dramatic. The rifle is the same weight as my .375 and I find the recoil quite manageable.
 

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I like mine too (although it looses the romantic competition to my double .470 NE), and I agree that it hits a lot harder, and I manage its recoil OK too, but would it be your choice for a one-rifle mixed bag 10 day safari WAB?
It will be my pick if I ever do an elephant hunt during raining season or in humid equatorial forest or marshland (I will not cry as much if it suffers, as I would do with the double), but I would not describe it as a "a very good compromise between killing power (and) usability" or "perfect cartridge for hunting all species in Africa," would you?
To me it is a great cartridge but it is definitely firmly entrenched on the heavy side of the spectrum, not really in the middle, the same way the .30-06 can kill everything in Africa, but is on the other extreme of the spectrum on the light side.
It seems that the typical compromise is more generally viewed around .375 or 9.3 (.366) x 62 or 64, would not you say?
 

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Good point One Day. I did take it as my sole rifle on a Mozambique hunt where I harvested a number of plains game in addition to buffalo. On subsequent mixed bag hunts I have taken two rifles. I must say that the Lott is very decisive on the likes of bush pig and bushbuck!
 

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Good point One Day. I did take it as my sole rifle on a Mozambique hunt where I harvested a number of plains game in addition to buffalo. On subsequent mixed bag hunts I have taken two rifles. I must say that the Lott is very decisive on the likes of bush pig and bushbuck!
+
Good point One Day. I did take it as my sole rifle on a Mozambique hunt where I harvested a number of plains game in addition to buffalo. On subsequent mixed bag hunts I have taken two rifles. I must say that the Lott is very decisive on the likes of bush pig and bushbuck!
I really like my 450 Ackley it is built on a Sako M995. I carried on for 61 days in the rain forest and ended up taking my derby with it when I could not get my 375 from my son quick enough. I always used 500 grn Barnes X but I now have some 450 loaded and going to try them.
 
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I like mine too (although it loses the romantic competition to my double .470 NE), and I agree that it hits a lot harder, and I manage its recoil OK too, but would it be your choice for a one-rifle mixed bag 10 day safari WAB?
... but I would not describe it as a "a very good compromise between killing power (and) usability" or "perfect cartridge for hunting all species in Africa," would you...

Well, with today's bullets it might be. Cutting Edge Bullets makes a tipped 258 grain raptor that is very accurate in my .458 and is devastating @ 2,950 fps in my gun. Because the bullet is brass, it is longer than a lead bullet at the same weight so the twist does not become an issue.
 

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What happened to the Asian guy that was on an elephant killing spree, did he ever get his hundred pounder? What was his username? I remember reading his post's about the time I first came on here
 

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What happened to the Asian guy that was on an elephant killing spree, did he ever get his hundred pounder? What was his username? I remember reading his post's about the time I first came on here

@michael458 will know more than me.
 

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stan elephant trail, or something to that effect, was the name, had some great stories

found him

@Stan-Elephant Trail
 
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All good calibers but I would opt for the Lott, because of the availability of ammo and components worldwide, and its a commercial caliber nowdays...for design the Watts but how big a positive is that, not much..
 

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View attachment 349664 When I googled .458 Ackley improved this thread came up.
I had not heard of of previously and my general understanding was Ackley improved was applied to various bottleneck cases with some exceeding others in various results of various calibre’s
Hi this is mad Hunter I bought that gun and would anyone be able to give me any load data for it any would be helpful
 

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