The 500 Jeffery Project Part II Handloads and Range Results - Good Grief!

I realize the .500 Jeffery is a major departure from my needs as a hunter, and clearly more than I want to shoot recreationally on a routine basis. It is, however, one of those bigger than life cartridges that got me interested in firearms when I was very young, and spending more time daydreaming than in useful pursuits. In writing this, some of my earliest impressions had to come to grips with an adult reality. Fortunately, the two weren’t that far apart.

The Jeffery has been with us for a very long time, yet there is not a great deal of detailed information available for technical research. In fact, much of it is the same basic data restated over and over in slightly different ways. The Jeffery is not a cartridge utilized by thousands of shooters who wish to share their collective wisdom. Published original data comes predominately from independent sources and frequently in conjunction with the promotion of a rifle, cartridge component or ammunition. Subsequently, working with the .500 Jeffery requires a sense of enterprise…sort of like Star Trek, but without Captain Kirk, but maybe with a little Spock.

The Jeffery’s operating pressure by current standards is modest. The round is extremely flexible, predictable and well-mannered. In a rifle of modern manufacture, the Jeffery can be nudged to comfortably outperform the higher pressure 460 Weatherby and keep pace with an even higher pressure .500 A-Square. The Jeffery, loaded even to 30-06 Springfield pressure levels, is able to push a 600 grain bullet to 2,500 fps and generate over 8,100 ft-lbs of kinetic energy. It can just as easily be loaded to reduced pressure levels and made into a spectacular plinker; 350 – 400 grain cast bullets at 1,400 – 1,600 fps. With the right bullet, and in pursuit of appropriate game, it can be quite flat shooting while hanging on to enormous levels of energy. Relying too much on published data and software simulation results will tend to mask the cartridge’s potential.

Bullet points…

I could not construct the definitive list of hunting bullets for the .500 Jeffery. Quite frankly, only a hunter with lots of kill experience with this combination would have enough anecdotal evidence to render an opinion and then only if they had been paying close attention to the way hunts played out, animals expired and the condition of recovered bullets. Bullet manufacturers get lots of feedback on their products, both positive and negative, and potentially have the greatest collective wisdom to offer customers. Unfortunately, but understandably, these companies are in business to sell bullets, not to consult, so they tend to make the best case for their own products. Sometimes the message is slightly disingenuous. Ever see a product that had been widely and expensively touted for six months by a manufacturer as the “best of the best” and their biggest seller suddenly disappear from their catalogue with little fanfare? In preparation to making bullet selections, I read articles written by experienced hunters that didn’t look like thinly disguised ads – the stories not the hunters, and reread some very enjoyable novels that included credible firearm and ammunition referenced. I also checked products for marketplace longevity and I attempted to analyze the logic presented by each bullet manufacturer within their product description while stripping away as many of the superfluous adjectives as possible. Finally, I called manufacturers and asked questions about specific products, and effort that I found to be the least rewarding. These days the tendency is to put a marketing intern on the phone who can only restate what the marketing department wrote and will fold like a deck of cards when challenged.

Generally speaking, or I guess that should be generally writing, bullet weights intended for .500 Jeffery applications weigh 600 or 535 grains. Bullets lighter than this weight are usually intended for the .50-110 WCF or .50 Alaskan and too fragile in construction for the .500 Jeffery. Bullets that fall between and beyond these weights are typically intended for the .500 Nitro Express. The real heavy weights in this caliber, those that hover around the 750 grain mark, are intended for use with the .50 BMG. Bullets for the .500 Jeffery and the .500 Nitro Express can be used when assembling .500 Jeffery handloads if the intended rifle has sufficient freebore and magazine length to accommodate a longer than standard COL. Performance of these loaded rounds will fall into the designed impact velocity of either type of bullets.

Best seats in the house…

Bullets intended for the .500 Nitro Express, a cartridge with a 3.750″ COL, are longer than Jeffery bullets and will extend further into a Jeffery case when seated to a functional length. The yellow line in the picture indicates the case mouth position for the handloads I assembled. The 570 grain bullet, right, is catalogued for the .500 Nitro Express. Seating the bullet out to take advantage of available SC 550 freebore and magazine length, reduced this bullet’s intrusion into the case. If I had loaded to .500 Jeffery COL specification, intrusion would have been 0.142″ greater. Doesn’t sound like much but this difference equates to 12 grains of available case capacity and 11,000 PSI of chamber pressure. Utilizing this extra space by seating the bullet out further yielded an additional 50 fps in some loads.

If a firearm will not accommodate a longer than specification cartridge overall length, maximum velocity won’t be achieved and 570 grain bullets intended for the .500 Nitro Express will max out at a lower velocity than a 600 grain bullet designed specifically for the .500 Jeffery. The Jeffery’s CIP drawing references a cartridge overall length of 3.468″ with consideration given to blunt round nose bullets. The same drawing vectors to a projected length of 3.624″. The SC 550 does not have work hard to accommodate this cartridge. The magazine has no problem with bullets seated out to a COL of 3.975″, however, the throat could not accommodate the same. I set my maximum COL at 3.700″ for all of the long bullets spec’d for the .500 Nitro Express. Both Barnes bullets loaded with room to spare. Not only did the banded flat nosed solid easily function at that length, it also offered the greatest net case capacity of the heavier weights. 

Two sizes fit all…

Big bore non-expanding solids are typically manufactured undersize. The objective is to reduce bore friction caused by a bullet that does not take rifling as easily as a more malleable jacketed lead core type. A solid’s diameter is one or two thousandths of an inch smaller than caliber and they are often banded where the surface of the bullet’s shank alternates between rifling groove and land diameter. The reduced contact surface area and friction cut fouling and boosts the bullet’s potential velocity. I always marvel at the discussion regarding the Triple Shock Barnes and it’s comparison to the original Barnes X and the effect on game. I bet I won’t be too far off if I guess the Triple Shock is no more than bands added to the X bullet to reduce a bore fouling problem and to get away from the expensive secondary dry lube process that was tried on their now defunct but really terrific XLC products.

In addition to undersize non-expanding solids, there is a big bore tradition of solid / jacketed companion bullets. While I can’t speak from first hand experience, there is an often expressed need to follow a jacketed bullet load with a solid bullet load in a gun’s magazine when hunting dangerous game. The concept advanced is that if the expanding bullet doesn’t do its job, the solid would be a convincing finisher. I believe the logic behind that theory escapes me. If the solid is the clean and sure killer, wouldn’t it make more sense to just begin and end with a solid? Anyway, for those who love folklore, British accents and dangerous game mysticism, the solid and expanding bullets are of the same weight to insure no shift in point of impact….which also makes little sense because there are numerous factors that control point of impact, bullet weight being only one of them. 

Ah yes, if only ad copy could kill. The hunter would walk up to the cape buffalo, posture a bit, then flash a copy of the bullet manufacturer’s ad appearing in the latest issue of “Shooting and Hunting” magazine. The buffalo, after reading about the bullet’s devastating striking power, would become deeply depressed over the threat, stop working out and eventually die from high cholesterol.

Notes on brass….literally

I think the term “big cartridge” can be aptly applied to the .500 Jeffery as I was able to write my load notes and performance results for each round right on the cartridge case. The overall experience with Bertram brass wasn’t exciting, not for $5 per case. The rims were thin, the extractor groove cuts varied from undersize to too large to fit into the correct shell holder. After one firing, the brass was so work-hardened it rang like a bell, a condition that was corrected with careful annealing. I know, from recent communications with Norma, the company still intends to ship the .500 Jeffery as part of their PH product line and that it will be distributed by Black Hills. It would be great if Norma would also supply brass for handloaders as they make a first rate product. A side note, all of the Bertram cases were badly tarnished as received, so they were rinsed in Iosso before loading. This should be done infrequently as the process strips zinc from the alloy and weakens the case over time, but I want a clean case to ensure stress cracks aren’t hiding under tarnish and carbon deposits.

The AmmoMaster II is not an unwieldy piece of equipment. The press has a lot of capacity for cartridge size, it has a lot of mechanical advantage for easy of operation, but it is big only where “big” means strength. The ram is 1 ½”, the cast base plate is 0.640″ thick at it’s reinforcing ribs and 0.400″ at the recesses. The triangular mounting pad provides a great deal of mechanical advantage in opposing force generated by the actuating handle. The top die plate uniformly 0.770″ thick, each of the three support rods are 0.690″ in diameter. The linkage arms are huge at 0.400″x1.10″, all steel parts have a black oxide finish for durability. Because the press also has a simple design with an emphasis on function, all of those heavy parts combine for only 18.7 lb. I often mount presses on simple wood roll carts, rather than drill my main workbenches full of holes for a temporary setup. The AmmoMaster was no exception. A few boxes of bullets and powder on the shelves for ballast and I could crank out ammo effortlessly. I should notch the shelf and set the press back so the load is more evenly distributed over all wheels.

The handload strategy – Bolt thrust and other ways to get into trouble…

In its early form, the .500 Jeffery pushed a soft nose 535 grain bullet to approximately 2,300 fps, which is actually pretty spiffy. In modern loading, the Norma African PH version propels a 570 grain bullet to 2,200 fps; both loads coming in at 6,100 – 6,200 ft-lbs of kinetic energy. There is no SAAMI recommended pressure range for the Jeffery. The 1998 CIP standardization is 46,000 PSI, a pressure limit that was established with 1920-something metallurgy and between war machine tooling, conditions that don’t apply today. Today, the .500 Jeffery is surpassed in performance by the .500 A-Square and .460 Weatherby Magnum, not because of lesser case capacity, case geometry or rifle strength, but rather by pressure levels based on specification. The .460 Weatherby, with 14% less capacity than the Jeffery, operates at a maximum 63,817 PSI. The .500 A-Square with a similar capacity differential operates at the same pressure level of it’s parent case, the .460 Weatherby, or 63,817 PSI.  The Jeffery hasn’t been surpassed, it just isn’t generally available in a modern loadings.

I tend to let firearms live up to their potential when I handload. In a modern rifle that can handle 50,000 PSI, I won’t limit a 45-70 Gov’t round to a Springfield Trapdoor limit of 28,000 PSI. I didn’t say I carelessly handload cases full of powder and hope a rifle can handle the load, nor did I say I loaded up until some telltale sign of nose bleed pressures made itself known. The Mauser magnum action is pretty tough. The bolt lugs and chamber walls were not being overly stressed by the .500 Jeffery’s 46,412 PSI CIP pressure standard and the bolt thrust of the big cartridge is actually pretty mild in relative terms.

460 Weatherby 12,123 psi
458 Lott 10,986 psi
500 Jeffery 10,612 psi
505 Gibbs 9,605 psi
416 Rigby 9,228 psi

While the case head diameter above the extractor groove is quite large, the internal case head planar surface, the surface parallel to the rim, is only .495″. The .500 Jeffery, for all of its size, is only mid-range in bolt thrust compared to other cartridges that have routinely made their way into use with the CZ 550 magnum action. Additionally, the .500 Jeffery is 0.021″ smaller in case diameter than the .505 rimless magnum (Gibbs), another cartridge chamber routinely used in conjunction with the CZ 550 magnum. This difference interprets into 19% greater wall thickness and increased resistance to stress that works on chamber walls.

Based on history, current chambering and some technical assessment of the firearm, somewhere below 57,000 PSI became my maximum pressure goal. I am not recommending this load level to anyone, not as an issue of liability, but rather I don’t recommend the approach unless the handloader has a way to closely control and measure progress. Predictive software such as QuickLOAD alone won’t get you there. While it is OK for preliminary assessments, it won’t replace a strain gauge or piezo transducer pressure check of a specific firearm, nor will it replace a good chronograph. In comparison to preliminary assumptions arrived at with QuickLOAD, chronograph and pressure data read approximately +/- 10% – 14%.

Handload results, the “Good Grief” part…

Joe, what does all of this mean?

Funny, I was thinking exactly the same thing. The .500 Jeffery is a very powerful cartridge and a convincing stopper. I am not sure the difference between this cartridge and the 460 Weatherby or .458 Lott justifies the dramatic cost difference for ammunition and handloading components. While the cartridge can be flexibly loaded for lighter and longer range duty, I don’t know if this serves a practical purpose. Light loading does not particularly diminish the cost of ammunition and handload components, nor does it remove weight from a rifle that is necessarily heavy to handle full up loads and not beat the shooter to a pulp. Light loading the Jeffery would be like paying $100,000 for a 500 horse power SUV then driving at exactly 55 miles per hour to save on gas. I think if I were prepping to go hunting for the largest game, or of I just liked handloading big bores and understood the associated cost and limitations, the Jeffery would be a great cartridge selection. If I needed something to do double duty and cover both heavy and medium size game, I’d probably look elsewhere. There is nothing in North America that warrants this cartridge and I don’t think there are many people who would want to haul a 10 lb gun around in pursuit of brown bear. It would seem for African dangerous game hunting there are also more modern, even if subordinate, cartridges.

As a ballistic note, the .500 Jeffery is fairly flat shooting. A Barnes 570 grain TSX can be zeroed at 200 yards and shoot that same distance point blank. Even at 300 yards, bullet drop is only 10″ and the bullet is still moving like a runaway freight train with 4,300 ft-lbs of energy. That is pretty spectacular big game cartridge performance.

On the other hand, the recoil even in the 10 lb SC 550 is a concern. I shoot a lot of heavy rifles, but the Jeffery is sincerely not fun after a few rounds at the bench. An initial smile is quickly replaced with a grimace and a search for soft things to put between the rifle and shooter’s shoulder takes priority. Recoil while hunting, where shooting is limited to a shooting a few rounds through an adrenaline haze, would not be a big deal or distracting enough to have a negative effect on accuracy. A day of development handloads is another story.

Accuracy of the CZ SC 550 and .500 Jeffery isn’t bad, even without a scope on the rifle to optimize group size. I was able to put together a number of 1 ½” three shot groups at 100 yards with the factory installed express sights. I am a good shot, but my eyes aren’t, so that’s impressive performance for me. Shooting a rifle of this type for accuracy is different than shooting more typical smaller bore high velocity magnums. With 140 – 150 ft-lbs of recoil, on discharge there is significant rifle movement, there is significant shooter movement, there is significant shooting bench movement and, I’m pretty sure, the ground moves just a little bit. My point is that it takes a lot more to get the gun back to it’s original point of aim after each shot which is not conducive to optimal group sizes.

I’m glad CZ-USA is producing these types of rifles and covering the really big bores at a price that is not out of reach…even if requiring some determined stretching. I think we are all fortunate that RCBS is producing quality equipment and tools for these cartridges so we can all pursue our enthusiasm for these rounds and maybe preserve a little part of firearm history.

The 500 Jeffery Project – Part I – When Way Too Much Is Just Enough
The 500 Jeffery Project Part II – Handloads and Range Results – Good Grief!
The CZ SC550 Safari Classic Part I
The CZ SC550 Safari Classic Part II