It looks close to a .338 Win Mag, but it's not quite right to be that. Obviously, it started life as .300 Win Mag donor brass. Remington (REM-UMC) was just too proud to put "Win" on the head stamp, being competitors to Winchester, and all (a fairly common occurrence amongst ammo manufacturers -- being loath to give any credit, what so ever, to the other guy.)
Like RC said, it’s somebody’s idea of a wildcat. You might not even be looking at the final product. Could be there’s another step, or two, before it’s done. Necked up. Necked down. Trimmed some more. Fire formed. Who knows.
Or, it could be just a “flight of fancy.” Having fun with a sizing die and a hack saw. Pure fiction. No real rifle at all.
You can see the logic in it, though. As wildcats go, this one kinda makes sense. A magnum case, shortened to fit a standard action length (.30-06ish).
Nice long neck. Good for those long heavy bullets a monster like this could be expected to throw. A fashionable sharp shoulder and little tapper. Everyone knows those are the secret-sauce for accuracy (looks cool, too!).
If a .300 Mag holds 89 grs of powder, and a .30-06 68 grs, then this mystery cartridge would hold something around 78 grains of powder. More than enough to gitter done with room to spare.
Put that in a light weight rifle and you’d be sitting pretty for hunting out west. Bring home an elk/moose/goat from the next ridge over, and only knock out a couple of your older fillings getting it all sighted-in in the first place.
I cant find it it either of my Lee or Hornady books.
