Ho-301 (40 mm)

Ho-301 cannon in the left wing of the Ki-44-II otsu, painted in red

Description

The Ho-301 is a Japanese 40 mm aircraft cannon intended for the anti-bomber role. It is unusual as it uses low velocity caseless ammunition and is solely mounted on the Ki-44-II otsu in-game.

Two Ho-301 cannons on the Ki-44-II otsu

Vehicles equipped with this weapon

• Ki-44-II otsu

General info

The Ho-301 has a relatively low fire rate and its rounds have very low velocity. Due to the design of the weapon and its ammunition, accuracy is poor at any range. The low ammunition count will cause this weapon to run dry in slightly less than two seconds of firing time.

Available ammunition

• Default: HEF

Penetration statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
HEF	3	3	3	3	3	3

Shell details
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	Ricochet
						0%	50%	100%
HEF	246	0.59	0.4	0.3	56	79°	80°	81°

Ho-301s firing, displaying very large muzzle blasts

Comparison with analogues

Due to this weapon's unique properties, it has very few true analogues in game. In fact, because of its low velocity rounds and high explosive mass, it is almost more similar to grenade launchers like the helicopter-mounted 40 mm M129 than it is to other large calibre aircraft cannons.

Compared to the rest of its class of bomber-destroying weapons, the Ho-301 has one of the lowest velocity rounds, largest bullet spread, and has some of the smallest ammunition count of its type.

Usage in battles

When using the Ho-301, it is recommended to manoeuvre very close behind the enemy aircraft to increase the chances of shells hitting the target. On the Ki-44-II otsu, these cannons act like secondary weapons as backup to the twin 12.7 mm Ho-103 machine guns. This weapon requires a significant amount of lead, even if the target is in straight and level flight. It is recommended to utilize the Ki-44-II otsu's agility to manoeuvre the rounds on target. As the Ho-301 was intended to be used against bombers, it is advised to use it as such if the pilot is intending to use this cannon as their main weapon.

It is not recommended to use the Ho-301 to attack ground or naval targets due to its very limited ammunition pool and poor accuracy. Its high explosive rounds, while having a great explosive filler, will only be able to damage unarmoured or open top targets.

Pros and cons

Pros:

• Shells have high explosive mass and can obliterate aircraft components
• Effective versus heavy aircraft
• Due to the Ki-44-II otsu being rarely encountered and looking nearly identical to other Ki-44s, enemy players may not expect to be attacked with this weapon
• Recoil can be used to slow the aircraft down

Cons:

• Slow fire rate
• Poor accuracy
• Low muzzle velocity
• Massive recoil makes aiming difficult
• Recoil will slow the aircraft down
• Very limited ammunition count
• Unusual performance may make it difficult to learn how to use
• No armour piercing ammunition for use against armoured targets

History

Photo of captured "40 mm Wing Gun" on "Tojo", February 14, 1945

Intended as an anti-bomber weapon, the Ho-301 is an unusual cannon that uses caseless ammunition. It saw limited use, mounted on specialized Ki-44 and Ki-45 aircraft variants and deployed against Allied forces in defense of the Japanese home islands.

The rounds use an aluminum cup to carry the projectile along with a silk bag holding the propellant and primer. When the primer is struck, the bag of propellant is ignited but the projectile is not launched from the chamber until the pressure causes the cup to burst through exhaust holes in the base.

The Ho-301 suffered from a low velocity and was only effective against bombers close ranges within 150 meters which would cause the aircraft to adopt a position well within range of enemy defensive weapons.

Despite its drawbacks, the Ho-301 became one of the few caseless ammunition weapons to see service with any nation.

Diagram of the 40 mm caseless ammunition

Media

Videos

The slowest guns in War Thunder | Ki-44 II Otsu - Joob

See also

Weapons of the same calibre and similar role

• Rolls-Royce Type BH
• Vickers S

Weapons of a similar role

• Ho-203 (37 mm)
• NS-45 (45 mm)

External links

• [Wikipedia] Ho-301
• TM 9-1985-5, Japanese Explosive Ordnance (pg.296)