When I grind my own meat for a "Blue Label" hamburger, the best tasting you can get, here is the recipe I use.
6 ounces beef sirloin, trimmed of gristle, and cut into 1-inch cubes
5 ounces beef brisket, trimmed of gristle, and cut into 1-inch cubes
12 ounces oxtail, fat and meat carefully removed from bone and trimmed of silverskin, bones discarded or reserved for another use (about 5 ounces of combined meat and fat)