The 338 Marlin Express is a modified version of the 376 Steyr, which was first introduced in 1999 and termed the "lion scout." The 388 Marlin Express is the outcome of a partnership between Hornady and Marlin engineers and was produced in 2009 to match the ballistic characteristics of the 30-06 Springfield for lever-action rifles. As a result, lever-action hunters would benefit from better performance over their 30-30 Winchester bullets.
Its concept was first propounded by Gun Writer Jack O'Connor, who desired to drive a 200-grain flat point or round-nose 33 caliber at a muzzle velocity of 2400–2500 fps with milder recoil yet shocking power and excellent brush penetration. The 308 Marlin that preceded this cartridge gave rise to the technology that made the 338 possible.
Hornady, the manufacturer, loads the 338 Marlin with a 200-grain flat point bullet that shoots at a realistic 2400 fps. This medium-bore cartridge’s superior ballistics begin to show beyond a hundred yards, as its ballistic coefficient allows it to maintain velocity at a greater distance than big-bore lever cartridges. The 200-grain Hornady FP breaks 1630 fps at two hundred yards to deliver an energy output of 1191 ft. lbs. At 300 yards out, the velocity drops to 1368 fps, and the terminal energy delivered is 831 ft. lbs. This makes the 338 Marlin Express a suitable 200-yard elk and 300-yard deer cartridge. The flat-shooting cartridge is chambered in the fast-handling Marlin 338MXLR and the Marlin 338 MX. With all this efficiency and killing power, the recoil produced by this cartridge is a mere 19 feet pound, the same amount of kick produced by popular small bores.