Thank you very much !
It's always nice to have someone who makes such specialities, and it will be exiting to follow your working process with the .620 RGB, and those huge 920 gr. bullets !
By the way,, i have to ask you about what loads you've developed in your .416 with your 353 gr. bullets, and performance. I own a .416 weatherby magnum myself.

fritz454,

The .620 Overkill bullet and brass you sent me are extremely impressive. The tolerance on the brass is so good that as I seat the bullet into the case mouth, it develops air pressure within the case because there is not enough space around the circumferene of the bullet for the air to get out!

I used a piece of scotch tape to hold the bullet in place and this round is very impressive. Compared to the 585 nyati, I would say the .620 Overkill is like comparing a 500 jeffery to a 458 win mag. It is just bigger in every direction.

Further, the extremely wide sharp meplat you put on the bullet will make a SPLAT! like no one has ever heard before when it hits a big fat hippo.

Like you, I hope to achieve 2000 to 2100 fps with 900 grains in a bolt gun. I will leave the 2400 fps work to Rob and the other guys.

So when is the deadline for ordering barrels? I gotta figure out how to swing this one on the homefront, any suggested approaches, lies et al are greatly appreciated. If you can also figure out an approach that includes the need for a lather with this bargain of a barrel, it would also be greatly, greatly appreciated

I'm back on the project finally! I got the NYATI brass out to everyone and am now done with that one. I have made some better case drawings for the .600 Overkill and have sent them to Dave Kiff to have a reamer and headspace guages made. This won't take too long. I've talked to Horneber about making some brass but have not heard back yet. Sounds like we have at least 9 folks interested in going ahead with the project and I received Fritz454's very interesting offer on brass and bullets. One interesting idea is to have the Pac-Nor barrels made with three grooves instead of the normal 8. I hear that the velocity gain is significant and as these are not long range rifles it seems to me like a good idea. I'd appreciate your thoughts. -Rob

Hmmmm.... Is extra velocity REALLY important with this monster?

On another note, I'm crazy enough to be interested in getting a barrel, but I'm left-handed. Are there any inexpensive things available in left-hand? I know the CZs are not. On the other hand, this beast would really just be a toy for me, so perhaps RH is OK.

So what's the realistic estimate for the whole project? Barrel, CZ, gunsmithing, etc.

Pertinax

Yeaahh , that's the way to go !!
Your my hero Robgunbuilder. You have the same interest for velocity gains (i think),as i do,but you also got the expertise and solutions.
So keep update me on the project,,what you and others have figured out so as to letting me know everything i need to know,,when i turn to my smiths here in Norway !
Could the case quality withstand the pressure of 2500 fps you think( with 900 gr. of course) ?
By the way ,Fritz could provide you with those facinating 920 grain bullets,,,(920 gr. at 2450 fps,!)

Rob,

would the barrel be available in stainless, I would want stainless if I were to get one to match my .585 ??

500 why do have to keep tempting me with all that splat talk, you blokes will keep me poor

Rob,
Do you have the dimensions on a CAD file? If you do would you mind emailing it to me. I can open files with .dwg, .dxf., igs, slddrw and a bunch of others but these are fairly standard. I will then tweak the brass program I have to match your final design. If it's a sketch or hand drawn print could you fax it to me. My fax number is part of my signature at the bottom of the email I sent to you.
Thanks, John

I want to know what the MAX velocity will be in the .600 Overkill with 900 grain Woodleigh SP and solid bullets...! 2450 fps with a 900 grainer will give 16266 joule But the .577 Tyrannosaur will as always give a higer kinetic energy. 750 grain bullet at 2720 fps will give 16740 joule. But sure, the .600 OK will hit much harder. It have more bullet weight and diameter.

Per577...!

A-Square is back... www.a-squarecompany.com Now I can buy a .577 Tyrannosaur if I want and the brass is not a problem any more...

Fritz- I have a scanned .jpg drawing and can send it to you later today. I'm off in afew minutes to buy more indexable tooling for the Lathe.! I'm trying to deceide right now if I should add a small amount of taper to the case or keep it straight. A small amount of taper might aid extraction and keep the reamer cutting smoothly along its entire length. I'm thinking of only a few thousanths taper from behind the belt to the case mouth. What do you think?
With respect to barrels, yes stainless is available but it will cost more. Any comments on the three groove idea? I think that it will add about 100fps to the cartridge. This in my mind means that it will take less powder to hit 2400fps than before which will equate to lower pressures. For those crazy enough to hot-rod this thing it probably means 2500 fps would be obtainable. God thats got to hurt.- Rob

2500 fps with a 900 grainer will give 16926 joule...! It will beat the .577 T-rex...

Rob,

I'm partially to a little bit of taper in the case, and perhaps a "ghost shoulder", ie parralel neck, then tapered from there back to the belt.

Have you contacted CH4D about dies?

Oops, double tap.

[ 09-18-2002, 22:20: Message edited by: GeorgeInNePa ]

Rob, I think a bit of taper would be a good thing. Helping with extraction being the biggest plus. This is especially true if the brass is turned.
I would agree with a three-groove barrel. Anything that lowers the pressure to achieve a desired velocity would be favorable. What will the twist be on these barrels?
A .jpg file is fine. Thanks.

John

I'm in for lower pressure. 3-groove is fine with me.

Yeahh !! "give me some sparkling(bad language)"
Sitate;guy from the movie"The jackal"with bruce willis testing his 14,5mm machinegun.
Well overkill, i must say it's a little bit early to know exactly if the .577 T-rex is obtainable for the moment, even their site at the internet is up & go !
And Robgunbuilder,2500 fps with 900 gr. bullets is quite some performance("i can't wait to try it").3-groves is the thing,,,go for it. And the one who fires full house loads, sure qualifies to join the "Jack ass" on the Mtv !

Rob,

I can create a CAD drawing for you if you like. I already got that thing modeled in a state of art CAD/CAM/CAE system. I can generate any CAD file formats including STEP, SAT, and IGES. Of course, it will be FREE just for you. Sorry I cannot get in on this deal as I have several projects going on right now. I also need to have a 500 A-Square first before considering anything bigger. Cheers! Ming

Paul,

The "deadline" was extended to October 15th to try to give more people time to get in on the deal. The cost goes down if we get to 12. We are at 9 confirmed now according to Rob. You are on your own for justification to significant other...I for one don't intend to tell her anything about it until the gun is built. A barrel is very easy to hide in the safe.

I for one don't want a stainless barrel, but they can be had for more money, I just think they are butt-ugly on a rifle, personal taste thing. As far as barrel grooves go, 3 or 8, either way is fine with me. I think I will stop at about 2200 fps myself with the 900's. That should be "plenty".

Gentlemen! There has been a 600 Belted Nitro Exp on ch4d die list for at least two years (as far as I know). Perhaps you should check this out before reinventing the wheel again. It sounds very much like a belted 600 Nitro doesn�t it...

http://www.ch4d.com/ch4d/Catalog/Page21c.htm

If I had not got the precision bug, I just might have been with you on this one. Now I must get the following pills into the hole of the first pill, at 1km+...

Well, after two or three years some bunch of men on this very forum will, no doubt, build themselves 20mm Vulcan rifles. Then I just might...

Big IS better! AKI

AKI- Before you get all high and mighty on us. What you have posted is meerly a name. I will ask Dave for a print. There are no cartridge dimensions listed. I know that Dave at CH4D has made a 600 by swaging a belt onto a shortened .50BMG case as I know others have. UNLESS you are certain and can prove that our dimensions are EXACTLY the same as the .600 Overkill which is designed specifically for the CZ550 action, I would appreciate your not implying that we are re-inventing the wheel. Since you don't even know what those dimensions are, It might be wise to remain silent.
Ming- I appreciate the offer and I used your original print to generate the dimensions I sent to Dave Kiff. I'll send you and fritz454 a jpg version of my hand annotated version of your print. After consultation with Dave and others I deceided to add a small amout of taper to the case and that is reflected in the drawing. Gee- I guess that it's now NOT just a belted 600 NE.-Rob

[ 09-19-2002, 21:27: Message edited by: Robgunbuilder ]

Rob, just checking to see if you got my e-mail a while back about getting a barrel.
300H&H

Rob,

I received the 585 brass and thank you. It looks good. From the shoulder I can tell it still needs to be fireformed, but it is a much better start than the bertram stuff.

300 H&H- Yes I receieved your E-mail. I think we will all order barrels in mass from Pac-Nor around the middle of october. This gives people enough time to get their finances in order.. There is a very substantial discount from Pac-Nor if we order 10 or more barrels. They will make the barrels threaded for the CZ550 action, 26 inches long, 3 groove 1:20 twist, 26 inches long in CM or SS. They will also short chamber the barrels for the .600 Overkill. The reamer will be available in about 4 weeks. I will make it available to those who get in on the deal for final chambering.
I've contacted Horneber about making cases and we will probably do another mass ordering as per the 585 NYATI project.
Let me know if you are serious about this or if you have any further questions.-Rob

Don't we need to have the barrels deep chambered so that we don't need to borrow the reamer, just face off the barrel?

Ditto to 500 grs, my understanding is they will be deep chambered?

Do we make checks payable to Pac Nor, and sent them direct to them?

My mistake! You are not re-inventing the wheel, you are modifying a very old wheel to fit a modern car of very old design. I humbly appologize!

My intention was merely to point to a possible source of not too costly reloading dies. IF anyone would have an interest in this, they got an adress, and they are free to dig deeper. I have not, so I wont.

However, I was invited by Saeed to participate on the old accuratereloading forum almost three years ago. I intend to do so until Saeed tells me to stop.

If my input sounded cocky or anything whorse it was NOT my intention. It�s not easy to get it right when wrighting in a foreign language, especially when it comes to subtleties like unintentionally stepping on someones exposed toes.

I love wildcats, and I�m constantly re-inventing wheels, large and small. I don�t care, because I love experimenting with special-purpose wildcats, and it is FUN. That�s why I love Saeeds fori, especially this bigbore forum. There is nothing like it!

Three years ago it was the Lott that was _The_ cartridge, then came the 500A2, then the Nyati, now the Ok. Will it stop here? Is this the ultimate cartridge? NO WAY!!!

Keep up the good work, and, above all, enjoy your magificent project! AKI

AKI,

Your input is not only welcome, it is appreciated. I did not know that CH4D had a 600 belted mag, and I would like to learn more about it.

Rob, I was talking with Ed Plummer over e-mails and he said he was just getting started working with the 600. If all goes well, I will probably have him fit the barrel and do the action work.
300H&H

AKI- Sorry to jump on you and I accept the explanation. I've just spent a heck of alot of time on this thing (much more than I thought) and your post hit the wrong note. As far as I know this wildcat has not been done before,however, it's not exactly rocket science and others are fooling with .600 NE derivatives. Let's forget it.
Paul H and 500 grains- I'm sure Pac-Nor will long chamber for you if you want it that way. When I spoke with them last they wanted to do a run of barrels as similar as possible. I have no objection to long chambering but if we want a discount from them, they may want as consistent a package as possible.
In any event, this is the next bridge to cross. I'll try to work out the details next week.-Rob

Rob,

If we short chamber the barrels, then we will each need to borrow the reamer in sequence, delaying some of the projects. Instead, I think it would be best to deep chamber the barrels, then each of us can purchase his/her own set of go and no-go gauges, so that no one will be waiting for either a reamer or gauges.

Can you tell us who is making the gauges so that we can each order a set? Thanks.

Rob, I don�t feel jumped on because I can realize your response. When in charge of such a project as this one, were most of the participants have not met (I guess), much time and money, and above all, thoughts and emotions are invested. I got a Brno602 two years ago, just because I read on this very forum about all the real big bores (505 Gibbs and 585 Nyati those days). On saturday it will be my rifle on moose hunt. It�s a puny 458WM, but it�s by far the biggest bore on the line, should be bigger though... AKI

500 grains- Dave Kiff at Pacific Tool is making the reamer and guages. Feel free to order one.
I understand your point about the long chamber approach and agree it's simpler that way. I'll discuss it further with Pac-Nor. However, they were not that keen on it when I first talked to them. In any event I will make the reamer available ( shipping and handling charges only) to those who go in on this project.
AKI= Again I apologize, unfortunately, projects like this attract some folks who seem to derive their pleasure from knocking the ideas of others. I know your not one of them and welcome to the project! Any help will be appreciated and we are making good progress.-Rob

[ 09-24-2002, 07:37: Message edited by: Robgunbuilder ]

Rob,

Got the sketch today. I will update the drawing and send you a copy. Thanks. Ming