What are the pro's and cons, which can be loaded to higher pressure (velocity?) If I had the barrel cut to 23" would I loose big velocity with these two boomers or is it neglitable.

I love big bores, I shoot 50 - 100 rounds a month with my lott, I also have a 375 H&H that see's almost weekly range time. The Gibbs or the Jeffery are next on my list and just wanted some advice.

Next year will be the 600 OK, I don't have the funds at the moment, on of the 500's will fill in for the time being.

The 500 A2 will be what most here will undoubtedly tell you to build. My recommendation would be a 500 AHR (an improved Jeffery). Of the two I would probably opt for the Jeffery over the Gibbs. Both will perform well though.

The Gibbs is about 25gr larger in case capacity, so all other things being equal will produce higher velocity for any given chamber pressure. You should plan on losing about 15 fps for each inch of barrel between 26" down to 22". Below 22" I am not sure what to expect, except a massive muzzle blast if using slower powders (say 4350 or slower).

Enjoy you project.

You will find 23" is fantastic ,. Danny Pedderson told me anything past 21" on a 510 wells is a waste. Go with "one faster" powde,r and you won't loose ONE fps..

500 Jeffery on the CZ is great, and a great buy .. i PERSONALLY don't have a gibbs as I shoot A BUNCH and there's no reasonable priced jacketed .505 bullet ...

I have a 500 jeffe, and loan my die bushing for the 505 .. and, of course, a 500 accrel, and about to rebuild a 500 a2/510wells (depending on which reamer i wind up with) on an enfield.

the cz in 500 jeffe is hard to beat, and at HUMAN levels, there's no meaningful difference between them other than choice ..

Personal choice - no big diff between the two.


I would go Jeffrey because of the larger range of .510 bullets.

I like the 505 gibbs for several reasons. Not even close.

1. Beauty. The gibbs looks way better. If its a beauty contest the gibbs wins. It is a nice long ctg. The Jeffery is short fat and rebated, with a short neck, a butt ugly ctg. Jeffery was a big compromise design to fit a std length action. The 505 is full length and takes full advantage of the CZ magnum action. Why go short if you have the room. You really need to examine some ammo.

2. History. More British guns were built in the Gibbs. More has been written. More hunted. It is a true British ctg. The 500j is almost a foot note in the old books that only real destination was about 1% more power that gave it title of biggest ctg for a while.

3. Reliability. The rebated 500J is prone too feeding problems. And to make it worse the CZ has a bad rep for reliable feeding. A double risk.

4. Magazine capacity. With some/most moderate price (non custom) guns, the 500J has just two rounds in a single column. This is becasue of the feeding difficulty. The 505 are going to be staggered magazine. I dont know about the CZ for the 500J. The CZ in 505 has a staggered magazine.



Edit:
You ask about max velocity. I have been told: if I could stand it, the 505 would have higher MV potential than 500J due to greater case capacity. If that's your criteria, then; 505 wins. Again, you really need to fondle some factory ammo.

Edit2:
I dont know how to spell Jefferey.

Having only a 500 Jeffrey I'll give you my advice on a few things.

1. Both the 500 Jeffrey and the Gibbs will shoot a 570g Barnes faster than your shoulder will want you to. The 500 Jeffrey gets the 570g Barnes TSX up to 2350 below 40,000 pressure. The CZ action and Jamison cases will handle lots more pressure.

2. The Gibbs will recoil more using the same weight bullet at the same velocity. Since the case is bigger it will take more powder which equals more recoil.

3. In a CZ 550 the bolt face will become very thin to handle the rim of the Gibbs. The CZ Custom shop told me this wasn't an issue and I have no reason to disbelieve them (the recoil issue kind of decided me).

4. I believe the Gibbs will naturally feed easier than the 500 Jeffrey, though mine feeds nicely using a mix of Barnes TSX's and Banded Solids. The CZ Custom Shop can make either feed, you may have to send it back once, but they'll stand by their work.

Anyway my two cents, but I have way less experience than lots of folks on this forum.

Regards,

Chuck

I have a CZ in 505 Gibbs, which qualifies me to discuss its' alleged shortcomings, mostly mythological or ignorance thru not owning one.

People talk about fewer bullet choices in the 505. BFD! You need one solid, period.

The Gibbs has a larger case capacity. In the end, that will be more MV and ME.

It has been discussed here, more than once or twice; about the Jefferys' rebated rim making it more problematical with regard to feeding. I've never fired one, whether it is an issue is gunsmith dependent the way I see it.

CZ makes both chamberings available. In todays' litigious society no company will offer a product that is not "Lawyer-Proof"!

The Gibbs just looks more like a DG cartridge IMHO.

Stick one in your front pants pocket and hit the bars on the weekend; initial testing results indicate you have an 11.6% better chance of picking up a hottie (defined as an 8.6 or better) with the Gibbs. The Gibbs just has the reputation.

What was it Hemingway wrote in "The Short & Unhappy Life of Francis MaComber" the PH's "short and shockingly big-bored 505 Gibbs.".

Get the Gibbs!

Rich

Get the .500 Jeffery. It's much easier to load for and that giant Gibbs case is an accident looking for a place to happen!

Rich's post goes to show you that one can't go far wrong with either ...

Thanks for all the responses, but I guess there is no clear cut winner, I comes down to personal preference.The Gibbs really does look the part, while the Jeffery hauls the mail.

Have any of you guys that own a Gibbs really pushed the limits with it, +60k psi? Is the Gibbs brass up to it?

DO NOT push a gibbs -- this is IDIOCY ..
boilt thrust goes up RAPIDLY with the gibbs, even more than the jeffery, and you have serious risk of galling/shearing the lugs.

ANY benefit of the gibbs is due to low pressure, and at a SPECIFIC pressure, it is both lower pressure an less bolt thrust than the jeffe ... BUT, get it hot rodded, and it will make a MESS.

what can the case do? look at the cheytac rounds, which are essentially high pressure gibbs cases.

quote:

Originally posted by fourbore:


The rebated 500J is prone too feeding problems. And to make it worse the CZ has a bad rep for reliable feeding. A double risk.

This is simply not true.

Dave,
any amount of money can eventually fix anything. The 500 jeffe IS without a doubt, prone to needing ALOT of attention to make feed. The CZ, however, as done by harlen, usually feeds perfectly .. but SOMETIMES may not. Because yours feeds great is NOT an indicator that it is not difficult to make feed. FUll stop.

Look, car drivers aren't sound advisors for mechanics, unless they are ALSO builders.

and yeah, there's some smiths who are so incredible that they have no problem with the 500 .. great, use them .. their work AINT cheap

Jeffe:

What's shakin down there in Texas? Did you guys have a big bore shoot this fall? Do you ever hook up with the double rifle guys like Mac or Mark and shoot with them?

I was going to do an AR cartridge but now I think I am just going to have Wayne Jacobsen do a 1,2,3, on my CZ .416 Rigby and call it quits. I have more guns then I can shoot. I am going to give MRC a couple of more months to finish my PH action but if they can't get it done, I will probably just cancel my order. If I ever get it, maybe it will be a .500 A-Square.

Dave,

are you off your meds schedule again?

The PH is designed, start to finish, around the Gibbs case; sort-of like the 1898 Mauser was around the X57 cartridge case.

Just be paitent, this ain't McDonalds.

Rich

Rich, I know you are right that the PH is perfect for the Gibbs. I'll get back on my meds

I started another thread and was hoping some of you guys might debate. I am looking for opinions on the 550mag. Feeding, performance, braggin rights, etc... Might be good choice for you Dave, Wby based like the 500A2.

I am pleased to note that Dave is now back on his meds and has seen the fallacy of his earlier statement.
Please note that the amber alert is now cancelled!

regards,

Rich

quote:

Have any of you guys that own a Gibbs really pushed the limits with it, +60k psi? Is the Gibbs brass up to it?

Doubledown, how much experience with big kickers do you have, if you don't mind my asking? For the 99.9th percentile operator the stock loading of the Gibbs or Jeffery is plenty. I strongly suspect that you would decide that the Gibbs or Jeffery loaded to 60+ ksi would be TOO much of a "good thing". The Gibbs should easily be able to beat the vaunted 500A2 by 150 fps with equal length barrels loaded to the same pressure.

I've run 600 gr 505s to 2600 fps and would have to agree with ScottS. The recoil velocity is so sharp that it is a far worse issue than just additional pounds feet at the muzzle. I suppose a muzzle brake would help but I can't stand them.

I don't think that was any where near 60k, either. Like Jeff said, the bolt thrust on a Gibbs is substantial and there is a smaller margin of error in actions not designed to deal with it. The PH will probably be one of the first other than specialty actions for the Chey-Tac.

ScottS, I don't mind you asking at all, I'm new here so I should

explain myself. I have no experience hunting dangerous game, I am

an avid coyote hunter though.



My experience with big bores is a Ruger 77 in .458 Lott, and a

Safari grade Browning in .375 H&H magnum. These two rifles get

shot at least twice a month, both are very accurate. I load for both

of them, and don't waste time shooting paper, to me there is no

better therapy than blasting oak 12x12's, water jugs, or steel targets.



I like to use a cartridge to its full potential, and was curious as to

why the Gibbs with all its powder capacity lags behind the Jeffery,

and is loaded down in the 46k psi range, jeffeosso said going much

higher could make things get ugly, thats why I like this forum, alot

of experience here and people willing to answer less than cutting edge questions like mine.

tiggertate , 600 gr @ 2600 fps is moving. The data Im finding for the Gibbs is 525 gr @ 2350 fps and that is'nt much better than my Lott. No one can complain about that 600 gr load thats for sure.

Norma sells a 600 grain load for the 505 (expensive), but I am sure its mild compared to handload potential. I see 505 gibbs reloads for the 600 grain at 2400 fps on this website:

http://www.470mbogo.com/BigBoreCompendium/

Nice summary of some big bore options.

I agree, it is with 600 grain bullets where the big 50s shine. And there are enough bullets to choose from in 505.

if you do get the 505, beware of the A-Square factory loaded ammo. It is sized wrong (too much headspace)and does not work in the CZ550 or at least that was my sad experience.

The 458 Lott loaded up to potential is a far cry from the 500 Jeffery or 505 Gibbs loaded to only 50 ksi or 45 ksi respectively in the recoil department. Those pressures are a far cry from what the cartridge cases are capable of withstanding also but your rifle's action may not appreciate much more than that. Your stock and bedding will appreciate higher pressure loads in the Gibbs and Jeffery even less than you rifle's action does.

As I have stated before both cartridges are very good tools and will kill anything that walks this earth quickly and cleanly with appropriated place shots. It really is simply a matter of personal preference. I have a 500 AHR and a 500 A2, and have used a 505 Gibbs. They are all excellent cartridges.

Best of luck with your project whatever you decide.

I can tell first hand, the Norma 600gr factory load in 505 Gibbs will out kick the 458Lott in similar CZ550. I have both and its a big step up to the 600 grain bullet.

Yup, I think Norma drives that 600 grain pretty quickly.

The standard 525/2300 Gibbs load is about like shooting a full house 500/2400 Lott if the rifles are the same. I think folks unfamiliar with the Gibbs associate the case size with recoil and that is misleading.

Doubledown: Hendershot's Sporting Goods in Hancock, Maryland has a good price on a used but mint 505 Gibbs CZ. If I remember correctly, it is $2150. You can see it on their web site under "used guns".

Agree with Scott, while a 458 Lott load is stoked shooting a 500g bullet at 2300 fps. My 500 Jeffrey shooting a 570g Barnes at 2350 is loafing below the Max specified for the older Jeffrey rifles and way below the safe load capable in a CZ 550. However a 570g at 2350 is definitely my SHOULDER's Max ... lol

Chuck

One more question, these two cartridges are a hundred years old and chambered for alot of older guns, is that the reason for the lower pressure, not unlike the 45-70 in a trapdoor.

In a 2009 CZ 550 a .500 Jeffery still needs to be loaded to 40k psi because? 600 OK. 500a2 both have much higher pressure built on the same action, what am I missing?

I don't think people buy a 505 or 500 anything to max it out. These guns can make enough horsepower at reasonable pressures. I have taken some of my big bores to the limit but found case life was not good and recoil was an issue. The price I pay for brass lets me know when to call it quits for pressure. A 500gr in the 460 is good to go at 2450 fps and pushing it till I have no room in the case for a bullet only gave me 2525. And recoil was sharper. 450's at 2500 are actually pleasant to shoot. I learned years ago that the big guns do not need 'pushing' and if you need or want more get a bigger gun. Maybe a few bigger guns.

There are higher pressure loads posted in the "Real Guns" page. I'm limiting myself to the Barnes Relaoding Manual #4 for the 500 Jeffrey. A 570g TSX or Banded Solid at 2350 is more than enough for me. I'm keeping my loads down to 2150 fps, much easier to shoot accurately and not painful at all off hand. It's hopefully more than enough for anything I will ever shoot with it.

quote:

n a 2009 CZ 550 a .500 Jeffery still needs to be loaded to 40k psi because? 600 OK. 500a2 both have much higher pressure built on the same action, what am I missing?

THis is wrong. The gibbs will handle same presure as 600 ok. as will all the choices you mention. Someone made some off-the-cuff political remark about pressure. It may have mislead you ( we all exaggerate to argue the merit of our favorites)

I get the impression you not did read this link(?):

http://www.470mbogo.com/BigBoreCompendium/

quote:

Doubledown: Hendershot's Sporting Goods in Hancock, Maryland has a good price on a used but mint 505 Gibbs CZ. If I remember correctly, it is $2150. You can see it on their web site under "used guns".

Did you check this? They can ship to your local FFL dealer. This is a great deal, I payed near 3,000 for my CZ and waited quite a while for delivery from Kansas City shop. The new list is over 3300. If you really want a big 50 and its for one year, you should think about this.

I would go with the 505 Gibbs. That rifle can shoot its bullets really fast.And its rounds are
bigger then the 458 rounds. You can get parts easer for it. It seams to be more Of them around.

I chose the Gibbs for all the reasons given above by various people both for the Gibbs and against the Jeffrey. I have been very happy with the choice. As for loads, I have approached 2400fps with 600gn bullets, but once over about 2340fps you can really start to notice the difference in recoil with every extra grain of powder. I settled on a load that gives 2270fps with the 600gn bullet. That's plenty for anything, and quite shootable. In the end as far as any game is concerned the end result is the same. If you choose a Jeffrey you just have to make sure it is properly made so it feeds perfectly. Aparently the Gibbs is easier to make feed perfectly, and that swung my choice in the end.