Also, the only real-world .577 caliber revolver I ever heard of was a five-shot Tranter made between around 1868 and around 1891. Articles on the Internet say the cartridge used a 400gr lead bullet—this is around nine tenths of an ounce of metal—and got it up to around 700 feet per second from the revolver's relatively short barrel. I find this implausible. Back in the 80s an American gun magazine staff writer obtained one and tested it. He had to have brass cases custom machined for it. He loaded it with .58" diameter cast lead round balls weighing about 300 grains each. With the cases packed with as much FFFg blackpowder as would fit under a lead ball that size crimped in place, the chronographs said it did 600-650 ft/sec in their tests. A heavier bullet would have occupied more space in the case, reducing available space for powder still further. A 400gr bullet .577" in diameter would have been very short and stubby in its proportions but still would have reduced the amount of powder that would fit in the case. And the cartridge is a very short and stubby one without much internal volume for powder. The powder charge was only 22 or 23 grains with the round ball, which is very light compared to contemporary cartridges. The .44-40 Winchester used a 200 grain bullet, .427" or thereabouts in diameter, and 40 grains of FFFg, giving vastly more velocity than the .577.