The .444 Marlin is a rifle cartridge designed in 1964 by Marlin Firearms and Remington Arms. It was designed to fill in a gap for the older .45-70 at a time when that cartridge was not currently available in any lever action, making it the largest at the time available lever-action cartridge. The .444 looks like a lengthened .44 Magnum and provides a significant increase in velocity. It is usually used for the Marlin 444 Lever-action Rifle.
In the mid-1960s the .45-70 had all but disappeared from the American marketplace. There was no big-bore cartridge available in a lever-action rifle in current production, so Marlin decided to create a new cartridge to fill this empty niche. They created what is essentially an elongated version of the .44 Magnum by making it nearly an inch longer to give it power similar to the .45-70. The case Marlin created is very similar to a rimmed .303 British trimmed and necked-up to work with .429 bullets.
Hunters initially had some troubles because the .444 was frequently hand-loaded using existing .429 bullets that were designed for use at handgun velocities. Remington has stated in letter and email, when asked, that their 240gr .444 bullet was not the same as a .44 magnum handgun bullet. Nevertheless, the rifle did gain in popularity as more suitable bullets were designed for its higher velocity.
In 1972 Marlin re-introduced the .45-70 to their lever-action line, expanding their big-bore offerings. Sales of the .444 are now overshadowed by .45-70 cartridge which has enjoyed a resurgence in popularity due to interest in cowboy action shooting. This quick action and powerful stopping power has been shown to be an efficient and useful hunting rifle for those who are experienced shooters.