The .450 Marlin
By Chuck Hawks
The .450 Marlin was introduced to make high pressure .45-70 (+P) performance available in a SAAMI standardized cartridge. The new case has nearly identical powder capacity to the .45-70, but looks like a shortened .458 Win. Mag. case with an extra wide belt. The latter feature is to prevent its being chambered in magnum rifles for which it is not intended.
The Hornady factory load for the .450 Marlin uses a new flat point version of Hornady's 350 grain Interlock bullet. Shooting Times magazine chronographed the Hornady 350 grain factory load at 2028 fps and 3197 ft. lb. of energy from the barrel of a Model 1895M rifle. Hornady figures call for 2100 fps at the muzzle and 3400 ft. lb. of energy.
The trajectory of the new cartridge is such that, if fired from a scoped Marlin lever action at a MV of 2000 fps, the 350 grain Hornady bullet can be zeroed as follows: 2.1" high at 50 yards, 2.9" high at 100 yards, and 4.8" low at 200 yards. This gives the shooter a 187 yard maximum point blank range with a load sufficient for taking all North American big game.
The SAAMI maximum average pressure (MAP) for the .450 Marlin is 43,500 psi. Hornady factory loads for the new cartridge are reportedly loaded to about 42,000 psi. Here are some other statistics important to reloaders: bullet diameter .458", maximum COL 2.55", maximum case length 2.10"
The .450 Marlin will normally be reloaded with bullets weighing 300-405 grains. Heavier (and thus longer) bullets must be seated very deep in the case to feed through the modern Marlin 1895 lever action, unduly restricting powder space.
Relatively fast burning powders such as H4198, H322, RL-7 and VIHT N-130 are indicated for use in the straight wall .450 case. Hornady testing revealed that H4198 and VIHT N-130 gave the best results.
Hornady reloading data from the sixth edition of their Handbook of Cartridge Reloading shows that the 300 grain Hornady FP bullet can be driven to a MV of 1700 fps by 38.5 grains of H4198 powder, or a MV of 2100 fps by a maximum load of 51.2 grains of H4198. This bullet weight would be most appropriate for CXP2 class game.
The Hornady 350 grain bullets can be driven to a MV of 1600 fps by 39.9 grains of H4198, and to a MV of 2000 fps by a maximum load of 47.9 grains of H4198. These figures were achieved in the 18.5" barrel of a Marlin 1895M carbine and used Hornady brass and Winchester WLR primers. Velocities should be higher from the more efficient 22" barrel of the Marlin 1895MR rifle.
Hodgdon reloading data shows that the 400 grain Speer FP bullet can be driven to a MV of 2023 fps by a maximum charge of 52.5 grains of H322 powder at a MAP of 41,900 psi. This load also used Hornady brass and Winchester primers; velocities were taken in a 24" test barrel.
Note: A full length article about the .450 Marlin can be found on the Rifle Cartridge Page.
Copyright 2004, 2013 by Chuck Hawks. All rights reserved.