A member of the Cast Boolits forums posted photos and video of a rifle and .700 caliber cartridge he designed. The only component he did not make himself was the barrel.
The cartridge, named the .700 WTF (“What The F…”) and is made by fire forming a .50 BMG brass case, trimming it to 3″ in length and then sizing it. The round is loaded with a 1132 grain paper patched .700 lead cast bullet.
The rifle, with just a 16.25″ barrel, can push the 1132 grain of lead up to 2300 fps. Thats 13,000 ft/lbs of energy, right up there with the .50 BMG and far exceeding the .700 Nitro Express. The cast lead bullet has enough energy to pass clean through a 1/4″ steel plate.
The rifle uses a shell-holder style action. My understanding is that the difference between a shell holder and a bolt action is that a shell holder lacks an automatic ejector and must be entirely removed from the action in order to load a new cartridge. Note how in the video below the shell holder, holding the cartridge, it loaded into he rifle.
The rifle is accessorized with a Magpul pistol grip (probably the largest caliber gun to ever be fitted with a Magpul accessory), a Limbsaver recoil pad and a Aimpoint comp M4.
Juding by the video case extraction is tough. If you miss your shot at a charging
Rhino T-Rex, you need to be able to reload quickly.
UPDATE: The inventor believes the rifle is not classified by the BATFE as a destructive because it is a sporting weapon. There is sporting weapons, such as shotguns and big bore double rifles, are exempt, the usual procedure it to obtain a letter from the BATFE stating that the particular weapon is a sporting weapon.
[ Many thanks to James T for emailing us the link. ]