Both the .243 and the .244 were introduced in 1955, the former by Winchester, the latter by Remington. The driving force behind both was Warren Page, who developed a cartridge he called the .240 Page Super Pouper (and that is the correct spelling, Pouper with a u, not Pooper; it was Lefty’s idea of humor). The Pouper was pretty much an Ackley Improved version of what is now the 6mm Remington; a long neck, very little taper, and about 10 percent greater powder capacity than the factory round. It was a very good cartridge, and Page touted it relentlessly. He took one to New Zealand where he shot most of the red stags on the South Island, and used it to lay low most of the woodchucks in New York State.