77mm

77 mm, or 7.7 cm, refers to artillery calibers in which the bore diameter is about 77 millimeters (roughly 3 inches). The designation has appeared in several nations for a range of weapons, including field guns, naval guns, and anti-aircraft or coastal defense pieces, dating from the late 19th century through the mid-20th century. Because “77 mm” is a broad label, exact bore size and design details varied by model, but most weapons in this class shared a balance of portability, firepower, and rate of fire suitable for supporting infantry or defending coastlines.

In practice, 77 mm guns were part of the transformation from heavier, cumbersome artillery to more mobile field pieces. They were employed by several major powers and saw action in the World Wars, with different nations adapting the concept to their own logistical and tactical needs. Notable examples include German 7.7 cm field guns from the pre-World War I era and various French 77 mm field guns developed in the late 19th and early 20th centuries. The class also extended to lighter naval and coastal guns, reflecting the versatility of the caliber for rapid-fire roles.

Ammunition for 77 mm systems typically included high-explosive and shrapnel shells, with some models capable of armor-piercing rounds or other specialized projectiles, depending on the era and design. Fire control and carriage arrangements varied, ranging from horse-drawn to mechanized carriages and later to more modern, recoil-compensated mounts.

Today, 77 mm calibers are of historical interest, having largely been superseded by newer standard calibers and evolving artillery technologies.