Can the Gibbs case be shortened to 2.90 and the neck expanded to .510? This would leave a neck length of .400. Is that enough? The 500 Jeffery had a shorter neck and was well liked as is the 300 Win Mag.

Snapper,

I am planning to build a rifle chambered in my wildcat 500 Dark Continent. It is based on a Gibbs case. I am cutting the case to 2.850 and the cartridge will have an OAL of 3.65-3.70 for use in a Magnum Mauser action. The neck length on my cartridge will be 1 bullet dia. or .510. This is simply a rule of thumb when disigning a wildcat but really comes into play with heavy kickers.

I'm sure I'm off a little but I'm measuring a 500 Jeffery neck at about .342, so a shorter neck length will work. I would like to go for a bovine grand slam before I die and I'm designing the rifle for this pursuit in mind. I don't want bullets being hammered back into the case causing high pressure and feeding problems at a crutial moment.

I chose the Gibbs case because I don't like the belted cases although they work fine. I know that beltless cases are easier to make feed well than the belted ones and the diameter of the belt takes up precious space in the magazine. I don't like the Jefferey case because of the rebated rim which has been known to cause feeding problems at times, it is also a little short in my book at 2.75 case length. I don't really need alot more powder capacity than the Jefferey but I have decided that I need more shoulder area as per a wonderful thread on designing cartridges that I read on this forum while designing this cartridge. Someone help me out with the subject tile. Also, the Gibbs case offers a .060 rim thickness over the Jeffery's .040.

So, the deminsions are thus:

Case length- 2.850
Neck length- .510
Shoulder angle- 25 degrees (for feeding and case life)
Head diameter- .635
Rim diameter- .635
Neck diameter- .535
Rim thickness- .060
Shoulder diameter- .600

I really think that this cartridge will work well for a DGR.

I want a 600 gr soft or solid moving at 2300-2350 fps with pressures under 50,000 psi from a 22 inch barrel. It might happen

When I get the money together for some parts to start with, I going to by a reamer and I'll have the dies made. I might want to go in with someone on the reamer cost if anyone is interested. I know it will be a few months after tax time before I'll have any desposable funds.

-Catter

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Shoot the largest caliber you can shoot well, and practice , practice, practice.

[QUOTE]Originally posted by Wildcatter:
Hi Wildcatter,
It sounds like you have your project sorted out pretty well. Try contacting Nickudu as to the extractor he installed in order to get positive feeding and extraction with his 505. If you want help or ideas on headstamping your own brass give me an e-mail.

470 Mbogo