|Place of origin||United States|
|Designer||Marlin, Remington Arms|
|Bullet diameter||.429 in (10.9 mm)|
|Neck diameter||.4530 in (11.51 mm)|
|Base diameter||.4706 in (11.95 mm)|
|Rim diameter||.5140 in (13.06 mm)|
|Rim thickness||.0630 in (1.60 mm)|
|Case length||2.250 in (57.2 mm)|
|Overall length||2.55 in (65 mm)|
|Rifling twist||1-38" (Microgroove) or 1-20" (Ballard cut)|
|Primer type||large rifle|
|Test barrel length: 24 in
Source(s): Hornady  / Remington 
The .444 Marlin (10.9x57mmR) is a rifle cartridge designed in 1964 by Marlin Firearms and Remington Arms. It was designed to fill in a gap left by the older .45-70 when that cartridge was not available in any new lever action rifles; at the time it was the largest lever-action cartridge available. The .444 resembles a lengthened .44 Magnum and provides a significant increase in velocity. It is usually used in 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.
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 making it well suited for all North American large game. SAAMI has rated this cartridge at 44,000 CUP. It functions efficiently when used with cast lead bullets. Hand-cast bullets allows 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 moulds available for the hand-caster: The SAEC #433 mould which casts a 300-grain (19 g) gas-checked bullet, 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.
Best cast bullet accuracy in the .444 Marlin is attained when utilizing bullets sized to .432" 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" diameter cast bullets. Full factory velocity handloads when assembled using hard-cast, gas-checked bullets of .432" diameter will rival accuracy of any jacketed ammunition for this cartridge.
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. 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, and Grizzly Cartridge offer loadings for the .444 Marlin in bullet weights up to 320 grains (21 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." and he describes its useful range as being out to about 200 yards (180 m). To put the power comparison in another way, the typical .444 Marlin rifle, has more impact energy at 200 yards (180 m), than a 4 in (100 mm) barreled .44 Magnum has at the muzzle.
- ".444 Marlin". Hodgdon Powder Company Rifle Data. Archived from the original on 20 October 2008. Retrieved 2008-10-17.
- ".444 Marlin". Remington Ballistics Data. 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
- Hornady (2003). Hornady Handbook of Cartridge Reloading. vol I (6th ed.). Hornady Mfg Co. p. 586.
- Remington ballistics table
- "A Hard-Hitter in Rifle or Gandgun by Dr. George E. Dvorchak, Jr. in Bob Bell, ed. (1997). Handloader's Digest (17th ed.). Iola, WI: DBI Books. pp. 172–176. ISBN 0-87349-192-0.
- Ackley, P.O. (1979) . Handbook for Shooters & Reloaders. vol II (8th Printing ed.). salt Lake City, Utah: Plaza Publishing. p. 213. ASIN B000BGII48.
- "The .444 Marlin" by Chuck Hawks
- .444 Marlin at The Reload Bench[self-published source]
- .444 data from Accurate Powder
- .444 Marlin- America's Most Versatile Big-Bore Part I :: By Marshall Stanton on 2001-06-27
- Nosler Reloading Guide 5th Edition; Book by Nosler Inc, LP, 2002 p. 487
- ".444 Marlin- America's Most Versatile Big-Bore Part I". Marshall Stanton. Retrieved 2001-06-27.