500 Jeffery or 505 gibbs

Davidm

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I have Brno zzk 602 in 458 lott already that I really enjoy shooting and hunting with. Now I have stumbled across another Brno zzk 602 but in 375H&H for a good price.
My plan was to rebarrel that one to either a 500 jeffery or a 505 gibbs. Which of the two would be the preferred choice when it comes to getting the action to work perfectly and with the least amount of gunsmithing?
 
Well CZ offer .505 Gibbs but I don't think they do a 500 Jeffery. might be a reason for this.
 
I'm not a fan of a cartridge with a rebated rim like the 500 Jeffery.
They are more prone to feeding and extraction problems.
Not a problem I would want to have when hunting things that one would normally hunt with a .500 caliber firearm.
I vote Gibbs.

Not sure if the rebated rim is the reason for the CZ being available in the Gibbs but not the Jeffery.
 
Short necks are for wrestlers.

505 Rimless Magnum!

:A Banana:
 
Well CZ offer .505 Gibbs but I don't think they do a 500 Jeffery. might be a reason for this.

They used to do both. I have a CZ 550 in 500 Jeffery.

full
 
Last edited by a moderator:
Jumping in for the comments as well. I don’t own either but intermittently check the market on both.
 
I’m travelling so I can’t check, but I think van der Walt’s book says that the rebated rim on the .500 Jeffery is no cause for concern. Perhaps someone can check my recollection? I certainly have no worries about it, and I put my trust in the cartridge often. As for the short neck, there’s no problem here, either. Plenty of bullet grip with the crimp in the groove.
 
Well since CZ makes a 505 gibbs then the bolt head of the 602 should be able to open up to accept that round
 
Interesting question. I hunted elephants and buffalo in Zimbabwe with a CZ 550 Mag in .500 Jeffery while my PH was using a well worn Bruno 602 in .458 Lott. He killed a lot of elephants, buffalo and a charging lion with that .458 Lott. I was his first client to use a .500 Jeffery. After he saw me shoot 2 elephants with that .500 Jeffery one frontal brain shot that missed the brain but dropped the elephant and gave me enough time to get a follow up shot in and a second elephant I heart shot and knock him off his feet, he said he saw a elephant get hit so hard before and he had to have one of those rifles. So he has one know and loves it. But I let him use it while I was there and he fumbled over the safety working the opposite on the 602 from a CZ 550 but other than that they are essentially the same rifle. The people at CZ USA custom make every .500 Jeffery meaning they are not mass produced. They take a standard CZ 550 magnum and skillfully open it up to handle the Jeffery. I have owned 2 of these rifles. The .500 Jeffery will function 100% perfectly in this rifle if the conversion is done properly. I believe CZ's custom shop may do that for you and it would be well worth it to have that experience craftsman do the work. The 500 Jeffery being such a beast no one sends a lot of range time with them. I'm good for about 3 shots at a session, but when facing an elephant or buffalo you don'r even notice the recoil. But to the point I fired maybe 300 rounds between the 2 that I have owned and absolutely no issues with feeding or function. I own 2 other CZ 550 magnums in 416 Rigby and 375 H&H, I have taken buffalo with all three. Now the important part which is better the .500 Jeffery or or the 505 Gibbs. Well the Gibbs is a pretty cool huge case and if it were .510" and not .505" I would go with that. But the .500 Jeffery uses the common .510" bullets which are much more available and can in weights up to 570 grains. This is a huge advantage. I hand load mine with 570 Grain Hornady DGS at 2350 FPS. This round did knock a bull elephant clean off his feet with a heart shot. Simply an amazing thing to see. My PH dose not use his old .458 Lott any more since he got the Jeffery. I have also used a .460 Wby in Africa and while on paper it may beat the 500 Jeffery with energy but when it comes to pure knock down power, the 500 Jeffery with 570 gr bullets can't be beat. The 505 Gibbs bullets are harder to find and the heaviest I've seen are only 525 grain. With the 500 Jeffery pushing a 570gr bullet at 2350 FPS your at the high optimum velocity to transfer energy, any faster than that is just wasted with these types of rounds.
 
Actually CZ makes the 550 Magnum in both 500 Jeffery and 505 Gibbs. the 500 Jeffery far out sells the Gibbs. CZ will produce the 505 Gibbs occasionally but they are very slow sellers. The 500 Jeffery moves on an off the shelves at a much faster rate. Also reloading dies for the 500 Jeffery is much more available but you will need a 1" press. Hornady and C&H make the dies. I highly recommend you get a Lee factory crimp die too, you can't rely on a roll crimp on this cartridge. Lee doesn't stock the die but they will custom make you one, a must have. Also the only reliable brass is going to be Norma. A few other companies make it too but I have personally see others have issued with other makes of brass in this caliber. So to be safe stay with Norma.
 
.500 Jeffery Hands down. I saw a Ryan Breeding Custom Mauser rifle at a gun show once. It's a work of art. I have heard that there is a bit of controversy about the ammo standardization though. Apparently , kynoch rounds don't chamber well in rifles regulated for Norma , and vice versa.
 
Hemmingway fan so 505 Gibbs for me
 
how do they compare in foot pounds etc
I have shot a .500 Jeffery only once , in 2009 but did fire off three shots from it. Stopping power is pretty much up there. The owner of that gun used it to drop a good number of Cape Buffalo and often got them in one shot. I have never personally fired a .505 Gibbs , but l saw it fired last year . It was a semi automatic rifle by Vigilance rifles using 600 grain bullets , which the maker calls " Bone crushers " .
I think l like the .500 Jeffery more because l heard that with " hot loads " it can supersede the .505 in stopping power.
 
First, read "The Short Happy Life of Francis Macomber" by Earnest Hemingway.
Second, buy the .505 Gibbs.
 
500 Jeffery all the way. I have one on a ZKK602 and it has given me years of perfect service.

More efficient cartridge than the Gibbs and it fires a larger bullet of heavier weight at higher velocity using less powder than the Gibbs.

Ballistic performance 500 Jeff
Bullet mass/type
Velocity Energy
570 gr (37 g) Soft Nose 2,200 ft/s (670 m/s) 6,127 ft⋅lbf (8,307 J)
570 gr (37 g) Barnes TSX 2,507 ft/s (764 m/s) 7,957 ft⋅lbf (10,788 J)
535 gr (35 g) SP 2,549 ft/s (777 m/s) 7,721 ft⋅lbf (10,468 J)
600 gr (39 g) PP 2,468 ft/s (752 m/s) 8,117 ft⋅lbf (11,005 J)
465 gr (30 g) Lehigh Solid 2,551 ft/s (778 m/s) 6,721 ft⋅lbf (9,112 J)

Ballistic performance 505 Gibbs
Bullet mass/type
Velocity Energy
540 gr (35 g) Norma Solid 2,300 ft/s (700 m/s) 6,345 ft⋅lbf (8,603 J)
600 gr (39 g) Woodleigh FMJ 2,100 ft/s (640 m/s) 5,877 ft⋅lbf (7,968 J)
600 gr (39 g) Woodleigh Soft Point 2,100 ft/s (640 m/s) 5,877 ft⋅lbf (7,968 J)
 
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 ASquare.

The Jeffery, loaded even to 3006 Springfield pressure levels, is able to push a 600 grain bullet to 2,500 fps and generate over 8,100 ftlbs
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 1,600fps. 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.

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 ftlbs
of energy. That is pretty spectacular big game cartridge performance.
.500 Jeffery 570 Grain Barnes TSX

Indices Range
Range yds. 0 50 100 150 200 250 300
Velocity ft./sec. 2500 2384 2271 2162 2055 1952 1852
Energy ft.lbs 7909 7192 6528 5913 5346 4824 4343
Path in. 1.5 1.3 2.6 2.2 0.0 4.3 10.9

Barnes TSX 570 .509 3.700" 133.4 IMR 4350 126.0 CCI 250 2522 8052

Woodleigh PP 600 .510" 3.490" 137.1 H4350 128.0 CCI 250 2468 8117
 

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