Type 90 Navy Machine Gun
Imperial Japanese Navy Arsenals · Machine Gun · Discontinued · 1930
Also known as: Navy Type 90 7.7mm Aircraft Machine Gun, Type 90 Lewis-pattern, RU Type derivative
Overview
The Type 90 was a 7.7mm flexible aircraft machine gun adopted by the Imperial Japanese Navy around 1930 as a defensive observer/rear-gunner weapon. It derives from the British Lewis gun, imported into Japan from 1921 as the RU Type and adapted for local manufacture: gas-operated, air-cooled and fed from a top-mounted pan/drum magazine. It was chambered in the Navy's 7.7x56mmR round, a Japanese copy of the rimmed .303 British. The Type 90 was the immediate predecessor of the standardized Type 92, which became the Navy's principal flexible aircraft gun through much of the Pacific War.
Specifications
| Weight (empty) | 8500 g (299.8 oz) |
| Overall Length | 980 mm (38.58") |
| Barrel Length | 620 mm (24.41") |
| Action Type | Gas Operated Long Stroke |
| Magazine Capacity | 97 rounds |
| Magazine Type | Drum |
| Muzzle Velocity | 745 m/s (2444 fps) |
| Effective Range | 457 m (500 yd) |
| Maximum Range | 3658 m (4000 yd) |
| Rate of Fire | 600 rpm |
| Barrel Rifling | Right Hand |
| Frame Material | Steel |
| Barrel Material | Steel |
Calibers
- 7.7x56mmR Japanese · primary — also known as 7.7mm Type 89, .303-pattern Japanese, 7.7x56R
Features
- Firing modes: Full Automatic
- Feed systems: Pan Magazine, Drum Magazine
- Features: Air Cooled, Lewis Pattern Action, Top Mounted Pan Magazine, Flexible Observer Mount
Variants
- Type 92 Navy Machine Gun — Successor
Service history
Operators
- Imperial Japanese Navy · adopted 1930 · as Type 90
Conflicts
- Second Sino-Japanese War (1937-1945)
- World War II (1941-1945)
Production
Production years: 1930-1945
Production totals not published; superseded in service by the Type 92
Origin
Country of origin: Japan
Discontinued: 1945
Notes
Lineage correction: the Navy flexible 7.7mm gun (Type 90/Type 92 family) is a Lewis derivative (gas-operated, drum/pan-fed), NOT the Vickers-derived weapon. The Vickers Class E/F copy is the separate Army Type 89 fixed gun. The Type 90 designation is poorly documented in English; most hard specs here come from its Type 92 successor and the RU Lewis import and are flagged accordingly. Bare-gun weight reported ~8.5 kg; with mount ~13 kg.
Background
Both of Japan's major aircraft-gun families were British in origin: the Navy's flexible Type 90/92 descended from the American-designed British-built Lewis gun (imported from 1921), while the Army's fixed Type 89 was a licensed copy of the British Vickers, so Japanese aircrew over the Pacific fought with British-rooted guns firing a Japanese copy of the British .303 cartridge.