Hwacha (화차) – Korean Rocket Artillery Wagon

The Hwacha (literally "fire cart") was a gunpowder-based anti-infantry weapon used by the Korean army during the Japanese invasions (1592–1598). It is considered the world's first multiple rocket launcher system.
The Hwacha was a two-wheeled cart with a mounted rocket-launching frame. The frame had multiple slots for small, metal-tipped rockets.
Some rockets were equipped with small bombs, while their metal tips could be dipped in flammable liquids before ignition. Effective Range: ~450 m
Number of Rockets per Salvo: 100–200
Weight: ~100–300 kg
Country of Origin: Korea
Period of Use: 16th–17th centuries

Organ Gun

The organ gun was a multi-barreled artillery piece used in the 16th–early 17th century. It was a forerunner of later volley guns, mitrailleuses, and machine guns.
To increase firepower, military engineers experimented with multi-barrel configurations. The organ gun had between 3 to 24 barrels, sometimes more, arranged in several rows.
The barrels were loaded sequentially, and each row had a connected priming channel, enabling either simultaneous or staggered volleys. Other designs included cross-shaped configurations or rotating barrels on a vertical axis.
Depending on barrel caliber, organ guns were either stationary (fortifications) or mobile (field artillery).
Caliber: 20–90 mm
Number of Barrels: 3–24+
Weight: Varied based on size
Period of Use: 16th–17th centuries

Bombard

A bombard (from the French bombarde) was one of the earliest large-caliber artillery pieces, widely used between the 14th and 15th centuries.
In a narrow sense, it was a large siege weapon with a short barrel (5–6 calibers in length). Early bombards fired lightweight 5-pound projectiles, but later models reached calibers over 500 mm, with projectiles exceeding 700 pounds (320 kg). Some massive bombards weighed over 15 tons.
Bombards were capable of both direct (flat-trajectory) and indirect (arched-trajectory) fire. They are considered the predecessors of all smoothbore artillery, including cannons and culverins (long-barreled artillery), mortars (short-barreled, indirect fire weapons), and howitzers (mid-range between cannons and mortars).
Caliber: 50–500 mm+
Projectile Weight: 5–320 kg
Weight: Up to 15 tons
Period of Use: 14th–15th centuries

Cannon

A cannon is a type of artillery piece designed primarily for direct fire (flat trajectory) against ground and aerial targets.
Unlike howitzers and mortars, cannons have longer barrels, higher muzzle velocity, and superior range, but lower maximum elevation angles.
The border between a howitzer and a cannon is often defined by barrel length: if the barrel is shorter than 40 calibers, the weapon is classified as a howitzer-cannon (or cannon-howitzer).