.310 Cadet

The .310 Cadet, also known as the .310 Greener, or the .310 Martini, is a centerfire rifle cartridge, introduced in 1900 by W.W. Greener as a target round for the Martini Cadet rifle. Firing a 120 grain heeled lead projectile at 1200 ft/s the round is similar in performance to the .32-20 Winchester and many rifles may chamber both rounds with some accuracy. This is NOT meant to imply that such a practice is generally advisable, or that both bullets are safely interchangeable, although for reloading purposes the 110-grain .32-20 bullet may be used in a .310 cartridge (being only marginally narrower).

The round gained popularity in Australia, New Zealand and the United States when thousands of Martini Cadet rifles were sold by the Australian government after World War II.