One of the first of modern 585 caliber wildcats, since WW2, the 575 Miller Greiss Magnum,
was first in records in the fifties, It was made from BMG brass shortened to 2.70" long
and necked up from 50 cal to .585" with what looks li\ke a little sharper shoulder..

They rebated the rim quite a ways to .618" to maybe fit 98 Mauser bolt.Used a special action.
Listed as a shooting 750gr bullet about 2400 fps. It holds about 150gr of ball powder under
a 750 gr bullet, maybe little less than 3" 50cal spotter case, where our 585HE holds
180gr under a 750gr'.

We made one for experimenting on a full length BMG case.With rim left same as the base
and would need a BMG sized bolt and action. I'm glad to be a big bore wildcatter,
and happy to be in the company of big bore nuts, old and new. Years ago when
guys did big wildcats they took what was available, to rework, and maybe
they could have used the 3" spotter case if they could have found couple barrels full.

But it takes a lot of work to reform cases that much, with the multiple dies,
multiple annealings and case trimming and extreme reworking of regular rifle actions,
which is why I like our cases, simple and straight, any regular long bolt action,
falling block, break action, etc, the 585 good for dozen or more heavy loadings,
moderate loads, last forever..

In making our 585HE we made it a size, a new belted size, to fit regular size guns,
not BMG actions,that didn't have to be used from a tripod, and could be put in a favorite,
the Ruger #1, other falling blocks, without taking metal out of the feed trough.
And to get the same and much more powder space like a cut back,
real short, fat, BMG wildcatted cases to 585, we made longer case and worked
with a group buy to get a factory run. We thank gun nuts for the help.

Here is picture from the great site, cartridgecollector dot net, of the M&G Mag .Ed

[Linked Image]

Ed Hubel