Thought I was finished with wildcatting,
but I will never feel like I have been there and done that until I have done yet another .510/.505 Gibbs, like so many before me.
Mine has to be unique.
Like no other.

Do I need one more stuffed-up "Olde English" nomenclatured cat to go with the 400/.395 Nitro Express 3-Inch Aboriginal, which is getting lonely for one of its own kind.

So here goes the
.505/500 Mbogo Gibbs
just because I want to call it that.

Any other .510/.505 Gibbs wildcatters out there?

Bolt thrust limits the .505 Gibbs to about 55,000 psi in a CZ 550 Magnum.
That's plenty, with such a large case and big bullet, for sporting purposes.

And of course the larger .510 grooves will allow either more velocity or less pressure, or both, versus the smaller .505 grooves,
for any given case capacity and bullet weight.

You only have 3.750" of COL, in a 3.8" box, even for the 3.150" case length of the .505 Gibbs.

A Gibbs case with a 500 Mbogo shoulder location will have a greater capacity than the .505 Gibbs "unimproved."

The shorter-for-weight .510 bullet adds case capacity too.

A case length of 3.000" and a caliber-length neck will have a greater EFFECTIVE case capacity than a longer-necked 3.150" .505 Gibbs.

How many angels are dancing on the head of this pin?
Is there any fly poop in this pepper?

DRG says: "Kiss my liberal grits!"

RIP,
If I was just absolutely compelled to build the .505 Gibbs, I would make it a .510 groove also. More bullet choices available and you can still call it a .505 without being too far out.

Hi Masterrifleman,
Phil Shoemaker succumbed to a BBK-02 built as a .505 Gibbs and sold in a Wasilla gunshop years ago.
He had some trouble getting it to shoot with .505 bullets, for reasons besides the sights.
Turned out it had a .510 barrel, probably a surplus military barrel turned down to sporty countour.
A competent smith subsequently sorted out the rifle's problems, incuding neck turning the .505 Gibbs brass, to thin the necks, so it would work in the reloading dies with .510 bullets.

Read all about it and the dramatic effects of Phil Shoemaker's .510/.505 Gibbs on brown bear ... in some old Wolfe publication.

DRG says: "Kiss my liberal grits!"

I like the idea. A slightly shorter Gibbs case from 3.15" to 3" with .500 Mbogo shoulder location= greater capacity with ability to seat bullets out bit if needed.
If I can ever wear out the .505 barrel on mine I would do the .510" version of the Gibbs.
Great idea Rip, I'll follow this one as I like the 50's.
Rodney.



505Gibbs
500AccRel
Future= something ridiculous

quote:

RIP: Read all about it and the dramatic effects of Phil Shoemaker's .510/.505 Gibbs on brown bear ... in some old Wolfe publication.

Pages 383-387, Practical Dope On The Big Bores, F.C. Ness.

Yep,
I have that book. Nicely yellowed with age.
That is not the inspiration for the .505/500 Mbogo Gibbs, however.
But thanks for reminding us of that reference.
DRG says: "Kiss my liberal grits!"

After that one, there is still the 550 Gibbs/510 (Rich's 550 necked to .510) or for the ultimate in reverse wildcatting, the 550 Gibbs necked to 505.

quote:

Originally posted by fla3006:
Pages 383-387, Practical Dope On The Big Bores, F.C. Ness.

Forrest,
I looked at that passage in the Ness book again.
It is mostly about P. O. Ackley doing a 40/.505 Gibbs in the 1940s, eh?
Ol' Parker Oliphant Ackley did the .408 Cheyenne Tactical back in the 1940's eh?

If I had a name like that I would be P.O.-ed too!

Maybe I should just do a .395/.505 Gibbs or "40/505 Gibbs" and forget about the olde English stuff ...

Proceeding at a snail's pace on many fronts here.

DRG says: "Kiss my liberal grits!"

quote:

should just do a .395/.505 Gibbs

Best idea I've heard yet. What's that case gonna look like ...??

OK,
Hurrah, .395/.505 Gibbs it is.
Macifej,
I will go dummy up a .395/.505 Gibbs and get back to you.
I am thinking, to be unlike the .408 CheyTac,
just a straight neck-up but have not decided on neck length, and might change the shoulder angle, but not base to shoulder distance ...
same headspace gauge and body sizer as the .505 Gibbs.

DRG says: "Kiss my liberal grits!"

The Genius Macifej has come up with a name for my cartridge, never before done.


.395 Berry Gibb
or
.395/.505 Berry-Gibbs
or
.395 Bee Gee

I be hummin' "Stayin' Alive" now!
I gots the "Saturday Night Fever" over this one,
and it is only Sunday!
And I be DANCIN' ...

Have to get out my old vinyl and find a record player ... nah ... digital ...

This project may merit production of the enigmatic HX M3 SHARRC bullet in .395" ... what will "The Man" say ...

quote:

Originally posted by Macifej:
IMG]http://static.rateyourmusic.com/album_images/9c426d92ef38f6c2f51639735d7e5e37/160300.jpg[/IMG

For some reason, all I see of the above image is a profound blankness. Will go look on another puter'. Initial and terminal brackets left off above IMG.

My thought after running a .505 Gibbs into a .416 Barrett die and then necking it down a little more with pistol dies:

Yes, indeed, just necking the .408 Cheyenne Tactical down to .395 would be super easy way to make a .395 Bee Gee.

On the top is a Jamison hull.
On the bottom is an A-Square hull subjected to equal stresses.
We have here the beginnings of a .395 BG-3.15"
versus a .395 BG-2.95"-ASS (Accordion Shoulder Sizing):



DRG says: "Kiss my liberal grits!"

How's about leaving the cool-o neat-o double Hoss Cartright neck in place ...??

quote:

Originally posted by Macifej:
How's about leaving the cool-o neat-o double Hoss Cartright neck in place ...??

I am going to have to sleep on that one.
Does have the look of a 3-stage ICBM with adequate payload for anything.

But .408 CheyTac is 70Kpsi brass in a 55Kpsi rifle, that's cool, and you could always go to a 50BMG-capable action to use the full 70Kpsi.
Easy barrel replacement would be a good option for such an action.
The 10-pound CZ sporter would be a one-shot killer so each barrel should be good for many safaris.

http://www.municion.org/408/Cheytac.htm

I think that CheyTac shoulder is about 20 degrees, like a .338 Lapua.
The .395 Bee Gee shoulder is definitely 20 degrees.
Slick feeding and less likely to ASS (Accordion Shoulder Size).

I think I would draw the .395 Bee Gee like a .408 CheyTac with shoulder extended forward to a neck brass diameter of .428" for both neck-1 and neck-2, and the case length would be
the same as for the .408 CheyTac,
76.86mm = 3.025" if municion.org link above is accurate dimensionally.

Will sleep on that too.

Ammoguide has some good dimensions.

408 Cheytac

If we're having a serious discussion about CheyTac's - any CheyTac - are we still talking about hunting?

This is not an idle question, nor it it in any way a knock on anyone's hobby.

My goodness, isn't the .78 Weatherby bad enough? CHEYTAC????

interesting idea, RIP.. sweet

Very interesting, RIP. I think though that I have enough with the .395 Max. Hopefully, when I get back from Iraq, my .400/.395 NE will be finished, also. This contract over here has seemed to get longer every day.
Max

quote:

How's about leaving the cool-o neat-o double Hoss Cartright neck in place ...??

Not original, Herter's did that with their "Ram Magnums" back in the 50's-60's. Butt-Ugly too!

quote:

Originally posted by Masterifleman:
Not original, Herter's did that with their "Ram Magnums" back in the 50's-60's. Butt-Ugly too!

Yeah man!
Thanks for reminding us of Herters.
Nothing original there, just the usual chuckle whenever those are shown!
Saeed goes hunting with double-shouldered loads of 404 Jeffery necked down to .375. Just fire forms while he is hunting.

I am going to take the easy route here and just do a .395 BeeGee that is a .395/.408 CheyTac,
with shoulder of 20 degrees,
none of this 21 to 25 degree stuff you find in various sources for the .408CheyTac.
If I ever get proper headstamped brass it will be marked simply ".395 BG."

quote:

marked simply ".395 BG."

aka .395 Bubba Gump

I want one .....

time is not kind to all...

quote:

Originally posted by jsl3170:
time is not kind to all...

True. Brother Maurice of the trio is dead of heart attack?
After 5 decades of singing, did Barry's high-pitched falsetto ever change to something more manly?
Oh well, at least it has some "recognition."

.395 BG
.395 Berry Gibbs
.395 Bubba Gump
.395 Big Gun

[IMG]http://www.beegees.com

What's a 300 Grain x .395" FN gonna do MV wise ...??

quote:

RIP: did Barry's high-pitched falsetto ever change to something more manly?

I always though he sounded like a lamb or goat going "bahaaaa"

FWIW I have a reamer for the 505 Gibbs/416 you can use.

Tigger, thanks but your reamer would wreck my .395 barrel!
Forrest, we'll just have to pronounce his name
"Baaaaaaarry Gibb"
to further distinguish it from "Berry Gibbs."
Macifej,
300-grainer at plus 3300 fps would make a nice varmint load.
Those 325-grain Rippers and 330-grain FNs at 3200 fps will be fun too.
In a light sporter It should do 378 Wby ballistics at around 50 Kpsi. Very pleasant.
A McMillan action and long barrel will be needed to get pressures up around 70 Kpsi.
DRG says: "Kiss my liberal grits!"

Wondering if this case would work in the G30 Mac Action or would it need to stay in the BMG Mac ...??

Will look into it.
Bolt and box big enough for BMG,
yet bolt face small enough for Gibbs?

That G30 is a tiny action.
An excuse for an MRC PH?

Did a little drawing and calculating.
Assuming the Ammoguide .408 Cheytac specs are correct.
The shown diameters at shoulder (.600") and neck-1 (.438") indicate a shoulder semi-angle of 22 degrees 3' 0",
using the base to shoulder distance of 2.430" and base to neck distance of 2.630"
to calculate the tangent of the shoulder angle = .40504
for the .408 Cheytac.
Ammoguide says 22 degrees. Good.

If I assume a .395 BG neck-1 is going to be .428" in diameter
[.438"- (.408" - .395") + .003" for thickening on necking down, which is what I got with the Jamison .505 Gibbs] ...

I gotta get some current Jamison .408 Cheytac brass to see what the neck diameter is going to be when necked down to .395 bullet.

Progress on the .395 BG will resume when Midway gets some brass to me, like later today if tracking is right.

DRG says: "Kiss my liberal grits!"

Still a serious shortage of larger actions out there ... the BMG actions I've handled are too clunky for a proper field gun.

I ran this up a couple of days ago using QuickDESIGN and cartridge data from AmmoGuide; it’s pretty close to RIP’s specifications.

capoward,
You are the first to publish a .395 Berry-Gibbs case drawing.
That is pretty damn good. Thanks.

Midway and UPS ain't doing so good today. The sun is down and the brass is still not here.

Mr. UPS Man delivered the brass 10 minutes after my last whine.
Have to wait until tomorrow to play with it.

quote:

Originally posted by capoward:
I ran this up a couple of days ago using QuickDESIGN and cartridge data from AmmoGuide; it’s pretty close to RIP’s specifications.

Necking down the latest Jamison .408 CheyTac --- tight on a .395 bullet ---
produces a neck diameter of: .422"
All of the new, unfired brass base diameters
are about .004" smaller than capoward's max brass dimensions.
His diameters would make a good reamer minimum.
Pictures:
An old .408 Cheytac dummy that was handed to me for free by Marc Jamison in Sturgis,
shows that it used to have a longer neck.
You can see the different headstamp below, old on the left, new on the right.
Dummy .395s use S&H bullets:
Longest VLD is .395/325gr "Ripper."
NonCon brass hollowpoint is the .395/310gr "Velohex."
The COL of the .395/330gr brass FN "Superpenetrator" is 3.777".

This works great through the CZ .505 Gibbs box.
The 330-grainer might go 3000 fps at less than 55K PSI.
That's in a 26" sporter contour barrel.
The GSC custom barrel profile would be perfect for that, with standard CZ threads.
This would be safe in the CZ 550 Magnum.

Since the combined wisdom of accuratereloading.com has pronounced the CZ boltface adequate for .505 Gibbs and 600 OK,
the CZ would be the easiest start on a
.395 Berry Gibbs Everlasting.
.395 BGE.

For a full power .395/.408 Cheyenne Tactical?
Lawton
BAT
and what other actions?
And what diameter barrel
and what length barrel
and which muzzle brake?

There is plenty on the internet about the .375 CheyTac ... cheers and jeers and hohum ... have not had time to look at it all.








Next:
Get a reamer made.
Screw the barrel off the CZ .505 Gibbs.
Screw on a barrel chambered for .395 BG.
Home rigged dies will work for fireforming.
Send fireformed brass to Redding for custom dies.
Get custom brass made for .395 BG headstamp to use in CZ.
Build "tactical" .395/.408 Cheyenne Tactical, to make full use of Jamison brass pressure capabilities.
Shall proceed at usual snail's pace.

DRG says: "Kiss my liberal grits!"