The American gun market made several famous dangerous gun cartridges around this time, such as the .458 Winchester Magnum, .378 Weatherby Magnum and .460 Weatherby Magnum. Many of these were 'wildcatted' (to modify an existing case and rifle to fire a different caliber bullet). The rest of the old Nitro express calibers faded to obscurity until people starting safari hunting in the 1970s and 1980s. Then elephant guns like the .416 Weatherby Magnum and the .416 Remington Magnum were made again. The .700 Nitro Express (made in the 1980's and 1990's) and the new brass manufacturers made even more powerful elephant guns such as the .585 Nyati by Ross Seyfried, .577 Tyrannosaur by Colonel Art Alphin and .585 Gehringer by Karl Gehringer to be made by wildcatters. The .600 Overkill made by Rob Garnick shows the biggest power that could come from a standard hunting action. Other wildcats based on the heavy machine gun .50 BMG and similar anti-materiel rounds have been devised which are much more powerful, though they are not generally useful hunting arms because they are heavier than .