585 NYATI
BY ROSS SEYFRIED
There was a lot of dust, raging screams and flying brush caused by nothing less than a very cheeky young bull elephant. The sight was magnificent; an 11-foot-tall, 6-ton roaring fury flattening everything in his path. There was only one thing wrong with the picture - all of this "entertainment" was pointed right at my frail body. I was guiding an elderly gentleman who couldn't run, leaving only one option - to play out this little fellow's bluff. Odds were very good that his only intent was to scare me - a mission at which he was totally successful. I fired the right barrel of my Westley Richards .450 Nitro just over his head when he clossed the 30-yard line. If my bluff didn't stop him, the left barrel was going to have to come down about 3 feet. If it didn't work at 10 yards, someone was going to die. Forturately, the Cordite boom had the desired effect and the bull retreated into the thorn belt.
The little .450 was nice, but during the next few hours my instincts for self preservation longed for my .577 Nitro. However, the rarity and immense value of a .577-100-750 double rifle dictated that it not be risked to charging elephants, or worse yet, African governments, any longer. That night, in a grass hut in Zambia, I conceived an inexpensive, lightweight .577 Nitro Express. This rimless cartridge was to be used in conventional bolt actions and duplicate the British round that is the stopper of all stoppers. I named it after my all-time favorite thing to be seen behind a set of express sights, the Cape Buffalo. He is called Nyati (n ya' te) in most languages of southern Africa. The .585 designation would set it aside from all of the rimmed versions that referred to the bore (not groove) rather than true bullet diameter of all of the .577s. At the end of load development it could also make a claim to "most powerful sporting round" with energy well over 10,000 foot-pounds. While energy claims are useless, it was an interesting comparison.
It is important to understand the difference between this and other so-called supperpower cartridges. Things like the .460 Weatherby, .475 A&M and oddballs like the .495 B-Round make their power claim by adding velocity to a "normal" bullet. Some have greater theoretical energy than the old .577 but do not have its bullet weight and diameter. These whip a solid through a buffalo or elephant faster but do not have that big .585-inch diameter to disrupt tissue. When facing dangerous game, bore diameter combined with bullet weight works, energy tables might not.
The parent cartridge was the .577 3-inch Nitro Express. The rim would be turned to .505 Gibbs dimension, leaving the cartridge with a slightly rebated head. By removing most of the body taper a .045- inch 30-degree shoulder could be formed. Here the "experts" said it couldn't be done. Such arguments as "Not enough shoulder to headspace," "It won't fit in the action" and just plain "can't" were thrown in front of my security blanket. I rebelled at "can't" and put JGS to the task of blueprinting and later grinding a set of reamers. The only argument that gave me the slightest concern was the small shoulder for headspacing, but in reality it takes a major effort on the handle of a loading press to move that shoulder.Around the huge circumference, the actual area of the shoulder is quite large. Headspacing is not a problem.
With the reamer grinding under way, I needed an action and barrel. The now-defunct Matco company make me a .577 x .585-inch, one-turn-in-20-inch-twist barrel. Several other barrel makers are tooled to make the big tubes; Krieger, Obermeier and Williams, to name a few. My rifle began as a purely "workhorse" experiment so the barrel was left the full 1.4-inch diameter, 27 inches long.
The action choice was easy. I had an old BRNO 602 on hand. While designed for the .375 H&H, the action is huge, with big wide rails that would handle the .660-inch diameter cases easily. The action would take a 3-inch-length case, but cutting it to 2.8 inches created a bit more body taper per inch. The choice between a 2.8 and 3-inch case wasn't easy, but I settled on a 2.8-inch case with a .500-inch-neck. At this length its powder capacity was equal to the .577 Nitro 3-inch - 160 grains, more or less! In addition to the BRNO action the .585 would also fit into magnum Mausers, Enfields and other capable of taking the .505 Gibbs cartridge.
A 3-inch version of the cartridge would certainly work. Higher velocity could be obtained and the round looks more impressive. However, the 2.8-inch cartridge fits into the actions with less modification and has the advantage of the bullet base almost touching the powder with normal loads. This helps prevent the bullets from being driven into the case under recoil. I hate to be practical where cartridges are concerned, but the 2.8-inch delivers more horsepower than anyone can handle. There is no need for a bigger case, and the short one will fit in a standard Mauser action.
As work progressed with the .585, an experimenter/collector in California hit upon a brilliant idea. He owned an original .500 Schuler rifle, which used the big .500 Schuler (aka .500 Jeffery) round with rebated head in a standard Mauser action. The Schuler system utilizes an extended magazine that holds the cartridges in a straight line rather than staggered in the conventional Mauser manner. With this patent it is possible to hold three very large rounds in the magazine, plus one in the chamber. A spring clip in the right side of the magazine box controls the rounds and their feeding out of the magazine. The Schuler uses a very rebated (smaller than the case body) case head that is the same size as the .416 Rigby. Jim reasoned that if the .500 Schuler cartridge worked on a standard 98 Mauser action, the .585 with a .416 head might lend itself to the same system....and it did. Gunmaker Sterling Davenport produced a grand 11 1/4-pound, four-shot .585 Nyati on a standard Mauser action. Yes, I mean one that was originally an 8x57mm military rifle! I will add details later, but this was a real boon to big bores - readily available, inexpansive actions. Best of all it put this gigantic stopper in the price range of ordinary custom rifles. A .585, with laminated stock, can be had for just $1,800. Certainly not peanuts, but just a fraction of what I would have expected to pay. A vintage magnum Mauser commands something like $2,000....for the action alone!
With the arrival of a set of reamers and headspace gauges from JGS my rifle was ready to go bang. Its maiden voyage was an unglamorous one - a 27-inch "axle," screwed into the crude BRNOaction, all tied to a tire and tripped with a long string. My initial load was the same as I use in .577 Nitro; 140 grains of 4831 and a 750-grain bullet. The young cannon made a deep throaty roar, lifted part of my backstop bodily into the air and disappeared rearward at a great rate. The recoil broke the nylon cord that held it to the tire and speared the barreled action into the dirt some 6 feet away. Not only was this unglamorous, but ominous as well. When I retrieved the rifle, the bolt lifted with one finger and the case ejected out of the port. With an inward grin I could only think, "Tell me it can't work."
My initial loading and forming dies were a combination of handmade dies ones reamed with the rough and finish chambering reamers. They worked, but when gleaming new ones arrived from RCBS the job of forming and loading was easy. A single forming die sets the shoulder, trims to length and begins the body taper. Full- length sizing and seating dies complete the operation. If you have a supply of B.E.L.L. ".505 Gibbs" cases, you are set. (The B.E.L.L. .505s required lathe-turning to reduce the body to make them .505 Gibbs; they are actually rimless .577s.) If you start with .577 3- inch rimmed cases it is necessary to form the heads on a lathe. Even though B.E.L.L. is out of business there are some of its .577s floating around as well as some vintage Kynoch brass. The good news is that Bertram in Australia is tooled up for .577. Quite possibly by the time you read this Huntington will have the new Bertram cases in stock.
There are more kinds of .585-inch bullets now than at any time in history. Mold makers can duplicate the old lead bullets. Barnes offers its plain vanilla lead/copper tubing bullets in 650 or 750 grains. It also has its grand solids in the same weights. An outfit called Naval Ordnance makes some interesting .585-inch bullets with drawn jackets in a variety of shapes and weights. This is the place for experimenters, because Naval Ordnance will make about anything you want. Then, the traditionally shaped but ultra-modern technology of the Woodleigh bullets is available. The shape duplicates the original Kynoch bullet, but internally they are the best made. They come in 650 or 750 grains. The steel-jacketed solids are almost indestructible. Woodleigh makes its softnoses with big blue noses, soecial tapered jackets and bonded cores. While most don't realize it, the bigger bullets like the .577 are quite apt to rupture their jackets on heavy game. It takes exceptional .577s to perform perfectly. The Woodleighs do.
Armed with an almost unlimited choice of components, I glass- bedded the barreled action into an original BRNO stock and began to chronograph and develop loads. The loads with 4831 were very mild, actually a bit slow. This prompted a change to 4350. I was hoping to be able to duplicate the 750-grain bullet at 2,050 fps that 100 grains of Cordite delivered in the Nitro Express. A load of 130 grains of 4350 came very close and again with pressure that didn't even take the wrinkles out of the case. Another 5 grains of powder put it just beyond the great Nitro round. Here was enough success to warrant completing the rifle.
The first step would be to cut the barrel to length and give it a proper contour. Brown Precision duplicated the dimensions of the barrels on my double rifle, resulting in a very light, elegant- looking profile. With the 23-inch barrel I began load development in earnest.
Shortening the barrel 4 inches reduced the velocity of my initial loads about 80 to 100 fps. Because pressure signs were very low I felt at liberty to add more fuel to the engine. I settled on 140 grains of 4350 and a 750-grain bullet as a working load for my rifle. Its velocity was 2,175 fps, far beyond the old Nitro's speed, duplicating the velocity of the smaller-bore .450 to .475 rounds. While I did not have the luxury of a pressure gun, all pressures indicators pointed to low levels. The cases fell out of the chamber and head expansion was negligible.
To the end of determining a margin for error and satisfying my curiosity, I continued to
increase the charges until I either ran out of case capacity or began to see signs of maximum pressure. With a case full of 4350 and 750-grain bullets, velocities were over 2,400 fps. Changing to Hercules Reloader 15 powder I hurled the big 750s over the 2,500-fps mark with energy in excess of 10,000 foot-pounds and a Taylor Knock Out number of 158 (compared to K.O. of 86 for the .460 Weatherby and 150 for the .600 Nitro). My load development was done with the rifle held in a machine rest and fired by remote control, for safety and to avoid recoil punishment. I fired one round loaded with a 750-grain bullet at 2,500 fps from an 11 1/4 pound rifle offhand, from my shoulder. It was an unforgettable experience. In the fraction of a second when the rifle was in full recoil, I thought it had hurt me. There was the monumental feeling that the rifle had gotten all over me. I couldn't see and the whiplash felt like a giant was trying to pull my head off. The recoil sucked me out of my shooting glasses and clapped my earmuffs over my eyes, accounting for the blindness. After taking off the blinders and checking all body parts, I found I really wasn't damaged. But it's an experience I don't care to repeat.The recoil approached that of a 4 bore, but with much higher recoil velocity. This kind of horse-power would require a 16 to 20-pound rifle. This of course defeats the purpose of the project. The Nyati is supposed to be light, handy and manageable. With 750-grain bullets it will break both shoulders on the biggest elephant. Why tamper with success.
While working up loads for the .585 I discovered an extremely useful helper. My limit is about six rounds of .577s per day. I needed an assistant that would accurately fire the rifle and not make me take all of the recoil. The good fairy brought a Stinger Rest just in the nick of time. This is a fixture that bolts to the benchrest. It has a front fork that supports the fore-end and a rear leather pouch that holds the butt stock. Built within the system are a pair of immensely strong springs. The shooter holds the rifle in a conventional benchrest way and takes a small part of the recoil on his shoulder. The Stinger absorbs the rest. Using the .585 with 750s at 2,500 fps the felt recoil, is about like a .340 Weatherby. Without the rest the loads would be impossible for most humans to manage! I fired as many as 50 .585 rounds in one day without a hint of gun headache or sore shoulder. Without the rest such a session would have been out of the question. The Stinger also allows extreme precision. It makes holding the rifle precisely on target very, very easy. I actually shot some 4 to 6-inch groupswith the big .585 at 300 yards....using a very large aperture sight!
Before I departed my pursuit of horse-power I wanted to try one more "bigger and better." This is using 650-grain bullets at abnormally high velocity. Barnes Bullets made me some 650-grain truncated-cone solids out of the same material it uses in its Super Solids. This is the bullet shape that outperforms all others in our big handgun cartridges and is proven to be equally effective in large-bore rifles. Using the less dense brass material the 650- grain bullet is about the same length as the 750-grain jacketed lead bullets. I haven't tried it on game, but with the .585 flatnosed Barnes solids moving at 2,400 fps we may have giant- tromping potential that goes right off the scale. The bullets have full .585-inch diameter, with an almost 1/2-inch flat on the nose. This, with the same velocity and more than 1 1/2 times the bullet weight of a .416 Rigby. Reducing the bullet weight from 750 to 650 grains keeps the recoil at a tolerable level. The added velocity and the big, flat nose will have a tremendous "splash" effect as it goes through tissue.
Today the grand double rifle is virtually out of the question, but the light, handy .585 Nyati is not. By using roughly 40 percent of the black-powder weight of 4198, filling the case with Dacron fiber and adding a patched pure-lead bullet we have the equivalent to the old BP loads. Both NEI and LBT can supply bullet molds. The accuracy is right up there with almost any modern rifle load; 1 1/2-inch groups at 100 yards are common. The solid, pure lead bullet mushrooms perfectly and because of its gummy nature does not fly apart. If we are looking for a deer and bear load for the woods, it might take some long searching to find anything as effective. When we consider this potential, added to a rifle that can be loaded with a recipe that will flatten a charging elephant under the worst conditions, the versatility of the .585 Nyatu becomes quite impressive. The only change required is a taller front sight to bring the slower loads to the point of aim. If one were interested only in using the light 550 to 650-grain bullets at sub-2,000-fps velocity the rifle could be made at 9 to 10 pounds weight.
The construction of the actual rifles is relatively straightforward. This is one case where an auxiliary recoil lug on the barrel is absolutely necessary. My original test stock was torn to splinters. Now the stock of fancy English walnut stands up perfectly, but it is thoroughly glass-bedded with Brownells Steel Bed. Added stock strength comes from crossbolts in front of and behind the magazine box and a barrel lug that has a tie-down screw through the bottom of the forestock. My rifle with the light barrel contour (.800 inch at the muzzle) finished at 11 pounds. The stock was made to fit me, with a large butt area, generous comb and Elmer Keith's anti-recoil cheekpiece. Even with all of these refinements the recoil was a bit more than I enjoyed. I added 2 pounds with #12 lead shot and epoxy, pouring some under the barrel and some in the butt. The weight was added in a way that maintained the rifle's balance just in front of the front guard screw. The 13-pound rifle certainly recoils with the 750s at 2,175 fps, but it does not rattle one's soul. I can make a relatively quick second shot and it weighs exactly the same as my grand old Rigby double.
The Schuler patent rifle made up by Sterling Davenport is a masterpiece in its own way. This is plain and businesslike, but awesomely effective. As I said, it starts with a standard Mauser action. A special extended magazine box is made out of solid steel that attaches to the original bottom metal by means of a massive lug and a single screw. A special trough-shaped follower replaces the conventional one. The rails are reworked and widened to admit the fat round. The spring steel retainer is welded to the right side of the magazine box to control the rounds as they come up under the bolt.
Sterling used a heavier barrel contour, fully one inch at the muzzle to accommodate his special integral compensator. This has an expansion chamber (enlarged portion machined into the inside of the bore just behind the muzzle) and two large oval ports on either side of the front sight. Unlike the little sharp-cornered "ports" often cut into the rifling, the combination of enlarged expansion chamber and large oval ports is quite effective. This rifle, weighing 11 1/4 pounds, seems to behave as well as or better than my 13-pounder. The Davenport compensator also suffers none of the side effects associated with the stress risers and sharp corners being cut into the bore itself. This workmanlike rifle is stocked with a laminated wood stock that seems unimpressed by any degree of recoil and has a very pleasant appearance.
Sighting on rifles of this recoil level has its limitations. In my opinion a conventionally
mounted scope is out of the question.

LOADING DATA FOR .585 NYATI

BULLET POWDER CHARGE VELOCITY NOTES

750 Barnes IMR-4350 130.0 1,925 Light
140.0 2,170 Mild pressure
150.0 2,287 No remarks
160.0 2,487 Maximum

750 Woodleigh IMR-4350 140.0 2,196 Mild pressure

750 Barnes solid IMR-4350 140.0 2,210 Mild pressure

750 Barnes RL-15 120.0 2,070 Dup.577 fact.
130.0 2,235 No remarks
140.0 2,420 No remarks

750 Woodleigh RL-15 MAX. 2,525 10,625 ft-lbs

650 Barnes truncated-cone IMR-4350 160.0 2,402 416 Rigby vel.

545 patched lead* H-4198 72.0 1,641 **Dacron filler

650 patched lead* H-4198 73.0 1,660 **Dacron filler

NOTES: All loads used B.E.L.L. brass and Federal 215 primers (*used Federal 210 primers) Velocities 15 feet from muzzle over Oehler and PACT chronographs. ** 15 grains Dacron fiber over powder to fill air space in case.

I posted the article up as it often seems to be requested.

For those who are not sure what to do, just drag across all the writing and turn it all black then go to "Edit" on tool bar and click "Copy". Then open Word and go to "Edit" and click "Paste"

Mike

I have the original article. But, Ross later recanted and said the .585 was an unmanagable rifle to shoot and the project was more of a "Can it be done project". Like many have said, the biggest bullet in the world is no subsitute for a proper bullet in the correct place.

Thanks Dude.

Thanks, downloaded and will be read!

Damn! ~~~Suluuq

According to Jack Belk, that gun at one time had a fiberglass stock of good quality and the recoil was so horrendous the after a number of firing the stock looked like a porcupine with fibers sticking out in every direction, to the point of total destruction of the stock, it just unraveled...now thats recoil...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Damn! Again. ~~~Suluuq

The funny thing is is that Ross has never taken his 585 Nyati to Africa,in fact it has never left the states!There is a picture of the completed rifle in his last article "So,you want a custom rifle".He claimed recoil was near unbearable and that the whole thing was pointless,espically since he never used it for what it was intended for.At least he got an article out of it all.

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I'm out to wrong rights,depress the opressed,and generaly make an ass of myself!

I have a .585 nyati that I load for and shoot regularly.
The recoil is not unmanageble in a properly built rifle. I have never experienced any problems with the stock(birch laminate). The rifle is very, very accurate if I do my part and I can�t see any reason why anyone who wish so shouldn�t use a .585 on big game.
I like mine - to each his own...
// J.G

/

Alf,
full-house loads with the .585 is only for stuntmen. I load to .577NE velocity max and stay below that for plinking loads. I have no muzzle brake, no mercury recoil reducer and the rifle wieghs in at 11.5 loaded - and it�s still great fun to shoot!
I will not, however, argue with anyone who claims that a 9.3mm or .375 is a far more useful caliber.// J.G

Well, gentlemen, I have a 585 on the way. I look forward to testing the rifle out. I look forward to posting some results.

JP

Mike 375 - Thanks for posting the article. I enjoyed reading it.

Alf - I agree. There may be a few out there who may be able to effectively manage a "hunting" rifle, so chambered, but "few" is the operative word.

[This message has been edited by Nickudu (edited 01-14-2002).]

JP,

What action are you using for your 585 and who is doing the work?

I took my 585 nyati to africa and shot an elephant and a buffalo with fine results. I was pushing 750 grains at 2250 fps. The recoil is about like an unbraked 458 lott.

I toyed with the idea of a 585 but gave it up for practicality sake.

I could shoot Mitch's T.Rex like a varmint rifle from the bench, but to do so requires a heavier gun with a muzzle brake, and I don't like to hunt like that.

Even with the brake and 14 pounds of gun weight, the T.Rex generated a lot of torque with full power loads. The rifle would twist to my right and jump to the right with each shot unless a lot of attention was paid to controlling this. And I still got a mild headache after about 10 shots, despite the brake and weight.

If one is going to load the rifle down to the old Nitro Express ballistics, I still think he would be better off with a big fifty: 500 Jeffery, 505 Gibbs, 500 A-Square. They are more than enough gun for anything.

The ultimate for power, versatility and practicality in a rifle one could easily carry all day and hope to control in a tight spot of shooting: 500 A-Square. This is only my humble opinion, I know my limitations.

The 585's are just not worth the HEAD ACHES.

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Happiness is a warm double.
RAB

That was a lot of fun to read!

DaggaRon,

I went very close to having a 585 made, but did come to realise that my neck was long finsihed for such things. Although my neck has come about fromyears of 375 pounding rather than the 378s and 460s.

However and for whatever it is worth I put the 585 Nyati in front of the 500 Jeffrey for a couple of reasons.

Firstly, shit brass is not such an issue as recoil will be too much even with air rifle pressue . That can't be said about the 500 Jeffrey. in fact with crappy brass a 500 Jeffrey will not have enough extra case capacity to have as much power as a 500 A Square with Norma 460s for brass.

I also felt that the sheer tradition surrounding the 500 Jeffrey demanded a higher level rifle than would be the case for a 585 Nyati.

I think the 585 would have lots of potential with 650 grain Woodleighs hollow pointed and a new weight of about 550 grains or so. Should be excellent for roos in the spotlight

The 585 I think is also good because it is basically the end of the road for bolt action rifles. That in itself could save a lot of money as compared to a 500 Jeffrey.

Mike

I own a lightweight unbraked .585.
I found that it could be managed easely if not pushed beyond 2200 fps. with 750 grainers. It only requires training and proper attitude.

After reading that and some contacts that Mike gave me, my hunting mate and I are going to have a .585 built this year. I will order a new cz .416 Rigby in the near future, I want the cz 550 action so it matches my .416 Rigby exactly. We intend to use this rifle so thought that 12-13 pound with a muzzle break would be neccesary and we still want to be able to walk around with it. You can always download to your own comfort level (people seem to think that 750@2200 is alright. Thats still very powerful), and I reckon the larger frontal areas make for spectacular results, it would be like a giant 45/70 on steroids and growth hormone. I am dying to see the effect of 750 grainers on ferals. Any more information on killing performance would be great.

Regards PC

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/

Alf,

As you have pointed out yourself at different times, these big bores are not be owned and used out of necessity.

Probably the easiest way to a CRF 50 would be to rebarrel a CZ 550 in 416 Rigby to 500 A Square.

In theory, a 500 Jeffrey would allow more power than the 500 A Square, but not if the brass is soft.

The fact that the extra power is not needed is a separate issue

But with the 585 Nyayi, the combination of very big case capacity and large bore will mean even if the cases were plastic the power obtainable will be huge.

Mike

Mike375 & ALF,
There are pro's and con's either way with all the big fifties and 585's. I just find the 500 A-Square to have the most favorable pro to con ratio.

I can shoot 750 grain target bullets at 2200 to 2300 fps and hit targets at 1000 yards with minimum wind drift using the BMG bullets, or fire 570 to 600 grain hunting softs or solids at 2400 to 2500 fps, with better penetration than the 585's.

A 2400 fps 570-600 grain load in the 500 A-Square is a less than 50,000 PSI load and should never cause problems in the heat.

The only way to stop something right now is a brain or spine shot.

A lesser rifle than a 585 is better for this, and a fifty is more than enough for anything else. Bigger bores are mostly stunt rifles anyway, and there is nothing wrong with stunt rifles when the stunts are properly performed.

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Happiness is a warm double.
RAB

Art Alphin pointed out that if God is on the side of big bullets, then a 585 caliber is appropriate.