.450 Marlin

The .450 Marlin was developed jointly by Hornady and Marlin Firearms in 2000 to give the Marlin 1895M lever-action rifle ballistics matching the belted .458 Winchester Magnum in a shorter case purpose-built to cycle through a lever gun’s tubular magazine and action, something the longer Winchester round cannot do reliably. It is not related to the earlier .45-70 Government beyond sharing a bullet diameter, despite both being lever-action-associated .45-calibre rounds; its case is instead built on the older, mostly forgotten .458×2-inch American, straight-walled and belted rather than rimmed. Marlin deliberately gave the chamber a distinctive belt-recess dimension so a .45-70 round cannot be chambered in a .450 Marlin rifle, closing off a dangerous handloading mix-up that a same-bore, lower-pressure cartridge would otherwise invite.

It exists to answer a specific limitation: the .444 Marlin, the lever gun’s other large-bore option, uses a smaller-diameter, higher-sectional-density bullet better suited to penetration than to rapid expansion, while the .450 Marlin’s larger 11.6mm bullet and belted case were built to deliver heavier, faster-expanding loads for dangerous game and large North American game at typical lever-gun ranges.

Every dimension in this entry comes from the C.I.P. datasheet for “450 Marlin”. Wikipedia’s infobox names four factory loads from Buffalo Bore and Hornady with a stated 24-inch SAAMI test barrel, but neither manufacturer’s cited product page could be independently reconfirmed live — Buffalo Bore’s URL now serves a reorganised catalogue and Hornady’s returns a 404 — so all four loads are recorded as estimated rather than verified, though each load’s velocity reproduces its own published energy figure through ½mv² almost exactly. No ballistic coefficient is published for any load.