The .310 Cadet cartridge, also known as the .310 Greener or .310 Martini, is a small centerfire rifle round developed in the early 20th century. It was specifically designed for use in the Martini Cadet rifle, a single-shot, lever-action rifle issued for cadet training in Commonwealth countries, including Australia and New Zealand.
The cartridge features a straight-walled, rimmed case that measures approximately 1.05 inches in length with a bullet diameter of around .323 inches. It typically fires a heeled lead projectile weighing around 120-130 grains.
Use cases for the .310 Cadet include target shooting and small game hunting. Its low recoil and adequate accuracy make it well-suited for novice shooters and youth firearm training programs. Although it has largely fallen out of common use, the cartridge remains popular among collectors and enthusiasts of vintage rifles.