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.^[3] The case Marlin created is very similar to a rimmed .303 British trimmed and necked-up to work with .429 bullets.^[4]

Some hunters initially claimed they had trouble 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 240-grain .444 bullet was not the same as a .44 magnum handgun bullet.^[3]

Despite the litany of false rumors about the 240-grain bullets, the rifle gained additional popularity as additional bullets were designed for its higher velocity.^[5]

In 1972 Marlin re-introduced the .45-70 to their lever-action line, expanding their big-bore offerings.^[3] Sales of the .444 are now overshadowed by the .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 experienced shooters.

The .444 Marlin can push a 240-grain (16 g) bullet at velocities over 2,400 ft/s (730 m/s) generating 3,070 ft⋅lbf (4,160 J) of energy. SAAMI has rated this cartridge at 44,000 CUP.^[6] It functions efficiently when used with cast lead bullets. Hand-cast bullets allow the shooter to optimize the alloy for strength and expansion at the higher velocities generated by the Marlin over the traditional .44 caliber bullets. There are several commercial molds available for the hand-caster: the SAEC No. 433 mold, which casts a 300-grain (19 g) gas-checked bullet, and the Lyman 429640 at 280 grains (18 g) are two of the more potent bullets for this caliber. Proper cartridge length is maintained by seating the bullet to the correct depth and using a crimp die to put a firm crimp on the seated bullet to prevent slippage in the magazine tube.

The best cast bullet accuracy in the .444 Marlin is attained when utilizing bullets sized to .432 in diameter, both in the older "micro-grooved" and the newer "Ballard" style barrels. This bullet diameter is dictated more by the large diameter of chamber throats than by groove diameter of the barrel. A projectile closely fitting the throat dimensions greatly enhances the cast bullet performance of this cartridge. Those writers and publications citing the inability of the .444 Marlin's micro-groove barrel to accurately shoot cast bullets driven over 1,600 ft/s (490 m/s) are simply in error, in that those results were largely obtained using .429 and .430 in diameter cast bullets. Full factory velocity handloads when assembled using hard-cast, gas-checked bullets of .432 in diameter rival accuracy of any jacketed ammunition for this cartridge.^[7]

Three years after the introduction of the .444 Marlin, Hornady introduced a new, heavier, 265-grain (17.2 g) .430 inches (10.9 mm) bullet created specifically for use in this new .44 caliber cartridge.^[1] Since then Hornady has also made a 265 grain (17.2 g) interlock "light magnum" that boosts velocity to nearly 2,350 ft/s (720 m/s) and 3,140 ft⋅lbf (4,260 J) of energy at the muzzle. Hornady's latest offering for this caliber is its new Leverevolution ammunition that has a soft polymer spire point that can be safely loaded in tubular magazines. Because of an increased ballistic coefficient, Hornady claims increased velocity at distances over 200 yards (180 m), and velocity and energy at the muzzle of 1,971 ft/s (601 m/s), 2,285 ft⋅lbf (3,098 J) and at 200 yards (180 m), 1,652 ft/s (504 m/s) and 1,606 ft⋅lbf (2,177 J) versus 1,542 ft/s (470 m/s) and 1,400 ft⋅lbf (1,900 J) for its interlock ammo.

Other specialized companies such as Buffalo Bore, Cor-Bon, Underwood Ammo, and Grizzly Cartridge offer loadings for the .444 Marlin in bullet weights up to 335 grains (21.7 g).

The newer .450 Marlin is also frequently compared with it. While it does not have the power of the .450 Marlin, the .444 Marlin is very similar ballistically to the .45-70, the almost extinct .348 Winchester, and is virtually identical to the .405 Winchester, in its 300-grain (19 g) loading. A 265-grain (17.2 g) bullet in .429 in (10.9 mm) has the same sectional density as a 300-grain (19 g) bullet in .458 in (11.6 mm) and can provide good penetration on large game. According to M. L. McPherson (editor, Cartridges of the World), "the 444 is fully capable against any species in North America"^[8] and describes its useful range as being out to about 200 yards (180 m). The typical .444 Marlin fired from a rifle has more impact energy at 200 yards (180 m) than a .44 Magnum has at the muzzle when fired from a 4-inch (100 mm) barrel.

• 10 mm caliber
• List of rifle cartridges
• Table of handgun and rifle cartridges

• ".444 Marlin". Hodgdon Powder Company Rifle Data. Archived from the original on 20 October 2008. Retrieved 2008-10-17.
• ".444 Marlin". Remington Ballistics Data. Archived from the original on 2007-09-30. Retrieved 2007-03-07.
• Cartridge Dimensions: Designing and Forming Custom Cartridges, Book by Ken Howell, Precision Shooting, 1995, ISBN 0-9643623-0-9 p. 359

• The Marlin Models 308, 336, 444, and 1895 at Chuck Hawks
• .444 Marlin, The Forgotten Big Bore