Hey !
I'm curious about the .505 Gibbs case and it's potential.The reason is it's huge case in proportion to it's poor ballistics, which list the .505 Gibbs to just 2350-2400 fps with a 525 gr.bullet. even at 2400 fps the pressure was over recommendations, to put it that way. While other gets a lot more !
So i hope there are people here been experimenting with this case lately, to post their ballistics.
By the way, are there companies producing cases to withstand 70.000 p.s.i in this case (Bell mast)?

Per577, I see you're not getting any answers yet.

My .510-.505 Gibbs dies are finally back from CH4D, and I should have preliminary results from my 32" barrel, Bertram cases, and 700 gr. M2 ball bullets in a month or so.

It seems like BELL is taking awhile to get the 505 brass out, but they should eventually have it. I think Ballard also makes brass for the 505, but can't remember the price. I heard Huntingtons carries the brass, but I haven't been able to find it at their site.
300H&H

Check out these two sites for what is being done using the 505 Gibbs case loaded to it's maximum potential.

http://cheytac.com/frame.html

http://www.prairiegunworks.com/index.htm

Cheytac says it is a "proprietary" cartridge, but the 408 Cheytac is based directly on an "improved" 505 Gibbs necked down to take .408" bullets. Prairie Gun Works did the same, but used much more common .416" bullets for their 416 PGW. Both companies were after a long-range rifle that uses a cartridge with a capacity between the 50 BMG and the 338 Lapua.