I remember reading an article many years ago by Jack Lott in Guns and Ammo and he had (I think) the 577 made rimless and necked to 475 on an M17 action. I think it was 475 LTD for Lott Tanner Dinosaur.

Kind of an early version of the Nyati.

Anyone else remember this article.

Mike

Hey Mike,
I do recall. The 1983 edition of a Petersen pub (a Guns & Ammo Specialty Book) called _Big-Bore Rifles_, a collection of Jack Lott pieces, has an article called "Ultra Magnum Wildcats" that refers to the original article in the _1973 Guns & Ammo Annual_.

The 1994 reprint of _Big-Bore Rifles_ edited out the picture of the cartridge and mention of the 475 LTD for some unfathomable editorial reason. Craig Boddington was the editor in 1983, but not in 1994. Good ol' Craig let Jack speak.

Here is what Jack Lott said in 1983:

"Over 10 years ago I designed an ultimate .475 caliber magnum wildcat for the late Hans Tanner which I called the .475 L.T.D. (Lott-Tanner-Dinosaur) and its story was published in the _1973 Gunns & Ammo Annual_. It was more of a stunt than anything else, but it was also a deadly, practical elephant/buffalo round which used the .577 Nitro-Express case with the rims turned off and made rimless. It equalled or slightly topped the the .475 A&M, but in a shorter, fatter case. Frank Pachmayr made an epic magnum rifle for it on a 1917 Remington Enfield action and mounted one of his Lo-Swing top mounts on it. This mount and the rifle withstood the horrendous recoil, but I must confess that not all those who fired it did! In mitigation, it must be pointed out that the .475 L.T.D. was intended only for Tyrannosaurus Rex, the brontosaurus and related varmints--not coyotes! I do not suggest this caliber as a serious option since making cases is difficult and the case head is really too big for existing bolt faces."

For more details find the 1973 G&A Annual.

So you are right, it must have been an inspiration for Ross to base the 585 Nyati on.

John J. Donnelly's _The Handloaders Manual of Cartridge Conversions shows the case to be 2.98" long, with a loaded length of 3.95". The 475 A&M is shown there to have a case length of 2.90" and a loaded length of 3.75".

So it would seem Jack had a shorter version of the 475 LTD also, just like Ross and his 585 Nyati.

Here are the specs from Donnelly for the 475 LTD:

Loading Data:
Bullet weight: 500 grains FMJ
Powder: 125.0 grains IMR-3031
Velocity: ---?

Source: Lott
Historical Data: By J. Lott in 1972-73
Data Source: Guns & Ammo Annual 1973, pg. 14.

Case Preparation:
Make From: .577 N.E. (BELL). Turn rim flush with body and re-cut the extractor groove. Anneal case and form in form die. Trim to length and chamfer. F/L size.

Physical Data (Inches):
Case Type: Rimless B/N
Case Length: 2.98
Head Diameter: .658
Rim Diameter: .658
Neck Diameter: .500
Neck Length: .500
Shoulder Length: .112
Body Angle (Deg's/side): .436
Case Capacity (CC's): 11.85
Loaded Length: 3.95
Rim Thickness: .05
Shoulder Diameter: .625
Length to Shoulder: 2.368
Shoulder Angle (Deg's/side): 29.16
Primer: L/R Mag
Case Capacity (Gr's Water): 182.83

I wonder how the scope and the foreheads of the shooters held up?

Now that certainly would be sharp little jab to the shoulder

I reckon that would be harsher than the .585 Nyatti recoil wise. Probably running out projectiles at highre velocities.

DaggaRon,
I have both of those "Bigbores" magazines and have been worried I may have missed a more recent edition. Apparently I have not(?). They are my most prized magazines and are said to be "collectors items". I hope another edition is in the works. Maybe I'll contact them and find out.

[ 06-12-2002, 07:31: Message edited by: Nickudu ]

Hello yaaa !

First of all this .475 L.T.D cartridge will outrun the .475 A&M Magnum easily.
Do someone know who will make a rifle in this cal.??
And what velocity is possible using 125 gr.of IMR-3031 ??(I want a hard kicking rifle)

Per "stuntman"577

Mike

I suppose it is possible that the 1973 G&A Annual had an article on the .475 LTD, but I am holding, in my formerly nicotine-stained fingers (to steal a line from Rush) the 1972 G&A Annual and on page 171 there appears an article by Jacques P. Lott titled "The World's Most Powerful Hunting Cartridge".

He actually made a rimmed and a rimless version. Only loading data (if you can call it that) was 140-150 grains of IMR 3031 for roughly 3000 fps. I think this was speculation (dangerous) vs actual load data.

The cartridge was born out of a bull session between Lott and Hans Tanner. They were drinking beer at the time...can you relate?

Tim

tarbe,
Maybe there was a two part series in the '72 and '73 G&A Annuals? There seems to be a hint of a short and long version of the 475 LTD in what I posted above. Has your 1972 G&A Annual got anything about maybe a 2.98" and a 2.80" version?

Here is one you yanks may not be familiar withand that is a 585 Nyati based on the 500 Jeffrey case.

There use to eb a gun place in Australia called London Guns. They made some Farquarson replicas in 577 and 600.

They also orchestrated quitea few 500 Jeffreys out here.

The "mini" 585 was the 500 Jeffrey taken out to 585 and headspaced on the mouth of the case, 30 M1 Carbine style. I suspect they used the Jeffey case because they were all set up for feeding and so.

Mike

Mike375,

Headspacing on the case mouth would not a DGR make! A real no no. So why bother?

You are right, never heard of that one! Pass.

RAB,

Why, what would be wrong with it. Positive headspacing of a belt with rimless configuration.

Mike

Mike375,
Headspacing on a casemouth is not at all like headspacing on a belt in any rimless cartridge.

Some slop would be allowable with the belted cartridge, but not the other.

Jam the case mouth into the bullet with a slightly long case and pressures will go up. That might lead to extraction problems.

Too hard a firing pin blow can drive the case mouth beyond the chamber into the smaller diameter throat, crimping the bullet. Now there could be excessive head space and excess pressure.

No crimp could be used if you head spaced on the case mouth (except a stab crimp, and brass could not be reloaded then). Not good for a DGR of heavy recoil. You know the drill.

Make the case too short in trimming and excess head space develops.

You would be mucking with the head space every time you assembled a cartridge. This does not happen with a belted rimless cartridge, or one that headspaces on the shoulder.

It will work in a 45 ACP or 30 carbine (basically a pistol cartridge too), but not a DGR. No way.

Head spacing on case mouth with a big bore rifle is strictly an experiment in precision, and a dangerous one.

RAB,

Some people might suggest that the 45 ACP or 30 carbine were designed as dangerous game weapons

Mike

Obviuosly Mike the short .585 never caught on, what were it's ballistics??

Does it give much up compared to the full powered Nyatti, say the diff b/w a .308 v 30/06

PC,

What are the ballistics of the 585 Nyati?

The 500 Jeffrey case taken up to 585 caliber will be the normal situation where the percentage increase in kinetic energy will be equal to half the percentage increase in bore area.

So, increasing from 510 to 585 will be a 31.5% increase in bore area and therefore energy will increase by about 16%.

If we stick with original 500 Jeffrey loading of 535 grainer at 2400 f/s = 6850 ft pounds, then the same case on 585 bore size will give with the same pressure 6850 X 1.16 = 8000 ft pounds approximately.

A 750 grainer with 8000 ft pounds would be doing about 2180 ft/sec.

Mike

The Nyatti can with the right powders push a 750 to 2500 fps. I doubt if one would get that with AR2209. RE 15 is probably the best powder for it, but it is to bloody dear here and you have to wait for it. IMR 4350 is supposed to work well to, Ar2209 is about the easiest option here. But like you said Mike most people can't handle the full power loads any way.

I am looking for a good working load with the 650 gr woodeliegh loaded to 2300-2400 & and If I can stand the recoil I would like to get to 2500 fps with the 650 grainer.