Marlin and Hornady deliberately designed it to prevent use in old .45-70 lever actions — a safety feature built into the cartridge itself via a wider belt.
Type: Rifle
Introduced: 2000, United States
Parent case: .458 Winchester Magnum
Standardization: SAAMI
Bullet diameter: 0.458" (11.63 mm)
Case length: 2.1" (53.34 mm)
Overall length: 2.55" (64.77 mm)
Max pressure: 43,500 PSI
Rim type: Belted
Primer: Large Rifle
Typical twist rate: 1:20
Muzzle velocity: 2000–2225 fps
Muzzle energy: 2664–4392 ft-lbs
Effective range: 200 yd
Common bullet weights: 300, 350, 400 gr
Primary use: Big Game, Dangerous Game
Production status: Active
Also known as: 450 Marlin
History: Designed jointly to give lever-action hunters a significantly more powerful option than .45-70. The belt prevents chambering in .45-70 rifles, which couldn't handle the higher pressure. Pairs with Hornady's FTX bullet for dramatically improved lever-action ballistics.
Notable firearms: Marlin Model 1895M
Similar cartridges: .45-70 Government, .458 Winchester Magnum, .444 Marlin