37×3

37x3 is a designation for a specific type of ammunition. The "37" refers to the diameter of the projectile in millimeters, and the "3" indicates the propellant charge or cartridge type. This ammunition is primarily associated with the Soviet/Russian 37mm autocannon, notably the Mle 1936 and its successors, which were widely used by various armed forces.

The 37mm caliber was popular for light anti-aircraft and anti-tank roles during the mid-20th century. The 37x3 cartridge could accommodate different types of projectiles, including high-explosive (HE) rounds for anti-personnel and anti-materiel targets, and armor-piercing (AP) rounds designed to penetrate the armor of light tanks and armored vehicles. The effectiveness of these rounds varied depending on the specific design of the projectile and the armor thickness of the target.

While the 37x3 caliber saw significant use, especially during World War II and the immediate post-war period, it has largely been superseded by larger caliber autocannons and more advanced anti-tank guided missiles in modern military applications. However, some historical collections and niche applications may still involve this ammunition. The design and performance characteristics of 37x3 ammunition are well-documented in military ordnance manuals and historical firearms resources.