The .308 Marlin Express cartridge was designed by Marlin Firearms and Hornady in 2007. It is based on the .307 Winchester with the intention of matching the performance of the .308 Winchester. To work in lever-action rifles, the cartridge has a slightly shorter, semi-rimmed case similar to that of the .220 Swift, as introduced in Hornady's LEVERevolution family of cartridges, the highest velocity production cartridge developed for lever-action rifles with tubular magazines. It's chambered in Marlin's Model 308MX and 308MXLR rifles, and it's fired from a Marlin Model 336 action.
The .308 Marlin Express is built on a new case, not a necked-down version of any prior case, albeit it looks very similar to a.307 Winchester case with a shoulder setback of.0998 inches. It is a rimmed cartridge with somewhat better performance than the .307 Winchester and comes close to the .300 Savage. Its claimed ballistics fall somewhere in the middle of those cartridges.
Hornady's LEVERevolution flex-tip spitzer bullet idea was used in the creation of the .308 Marlin Express. This has been re-optimized, particularly for the .308 Marlin Express, resulting in a flatter trajectory with more maintained velocity and energy downrange. The new 160 grain .308 Marlin Evolution bullet features a larger ogive and a greater ballistic coefficient (BC.400) than the .30-30 Evolution bullet from last year. The BC of the 160 grain .30-30 Evolution bullet is .330..
On a number of large game species, the newly redesigned 160-grain Evolution bullet has already been shown to be quite successful. As a result, the .308 Marlin Express became the newest, quickest, flattest-shooting, and most adaptable of the rimmed hunting cartridges designed for use in lever-action rifles as a result. It transforms the Marlin 336 rifle into a real "all-around" weapon for hunting CXP2 (deer) and CXP3 (elk) animals.