5.25 inch/50 QF Mark I (133 mm)

Description

The 133 mm 5.25-inch/50 QF Mark I is a British naval cannon used by Royal Navy vessels. Lying somewhere between destroyer and light cruiser calibre, this cannon is only equipped in-game to the HMS Dido, the British rank III light cruiser. During its real-life service, it was also used as a dual-purpose gun, equipped to the King George V-class battleships, as well as HMS Vanguard, the Royal Navy's last battleship.

Vehicles equipped with this weapon

• HMS Dido

General info

The 5.25-inch guns are 133 mm in diameter, placing them close to both the 5-inch (127 mm) guns used by the American, Japanese, and German destroyers, as well as the 130 mm guns used by the Soviet destroyers. As a result, these guns are some of the deadliest guns in the game against destroyers, thanks to their hefty size and rapid rate of fire. However, these are still small guns for a light cruiser, lacking in firepower to the many 6-inch (152 mm) guns found on other light cruisers. While the rate of fire of these guns is also impressive (especially with a good crew), it isn't enough to truly outgun any light cruisers firing back. As a result, these guns are best used as anti-destroyer guns, using their good damage and adequate rate of fire to punish enemy destroyers.

Available ammunition

Like many of the British destroyer guns, the 5.25-inch cannons lack any true armour-piercing shells. Instead, players get the option of three shell types:

• HE - these shells are the stock shells for the 5.25-inch gun. While they can deal huge damage to destroyers and coastal craft, they lack the penetration or the sheer damage to damage any armoured cruisers. However, there are still some light cruisers that can take big damage from these shells, such as the British HMS Enterprise, the Japanese IJN Kuma, and the American USS Raleigh and USS Trenton. These shells can also do substantial damage to auxiliary and AA guns, smoke stacks, and lightly armoured gun turrets.
• SAPBC - these semi-armour piercing shells are the best shells for use against larger light and heavy cruisers, with enough close-range penetration to cut through belt armour on larger ships. At range, these can also be devastating to light cruisers and destroyers, with the ability to cut through hull armour and hit ammo racks and elevators, as well as ship engines and rudders.
• HE-TF - the time-fused shells, like others of the type, are the most effective against AA, and can also be used to dig into destroyers and damage more internal components if at close range.

Penetration statistics
Ammunition	Type of warhead	Penetration @ 0° Angle of Attack (mm)
		1,000 m	2,500 m	5,000 m	7,500 m	10,000 m	15,000 m
5.25 inch HE	HE	35	35	35	35	35	35
5.25 inch Mark II SAP	SAPBC	171	149	118	95	78	59
5.25 inch HE-VT	HE-VT	35	35	35	35	35	35

Shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile mass (kg)	Fuse delay (s)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (kg)	Ricochet
							0%	50%	100%
5.25 inch HE	HE	814	36.3	0	0.1	2.95	79°	80°	81°
5.25 inch Mark II SAP	SAPBC	814	36.3	0.025	5	1.47	48°	63°	71°

Proximity-fused shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Arming distance (m)	Trigger radius (m)	Explosive mass (TNT equivalent) (kg)	Ricochet
									0%	50%	100%
5.25 inch HE-VT	HE-VT	814	36.3	0	0.1	274	18	2.95	79°	80°	81°

Comparison with analogues

• 130 mm/50 pattern 1913 - this Soviet cruiser gun is a similar calibre to the 5.25-inch. While it lacks the British gun's calibre, it makes up for it with better armour penetration and a better shell velocity.
• 130 mm/58 SM-2-1 - another Soviet 130 mm gun, this outclasses the 5.25-inch gun entirely, with superior rate of fire, penetration, shell velocity and ammunition.
• 5 inch/38 Mk. 12 - this American 127 mm gun, found on the USS Atlanta, lacks the raw firepower of the British gun, and has a lower shell velocity, but its insane rate of fire (22 rounds/per min in first stage) means it can easily beat the British gun in a duel.

Usage in battles

The 5.25-inch gun, like the guns on the USS Atlanta, sit contrary to the role of its only user, the HMS Dido. While the guns possess good damage and rate of fire for their calibre, they still shoot slower than destroyer guns, and hit softer than cruiser guns, leaving them in an awkward position. Still, these guns can fill any role effectively.

Against other ships, these guns can still be effective. Destroyers should be terrified of these guns, thanks to their good shell velocity and rate of fire, and their fantastic damage and accuracy. The Dido can easily pick apart destroyers, and these guns can effectively outgun many destroyer guns at range. However, these guns lack that same effectiveness against cruisers. The SAPBC shells can damage cruisers, but they lack explosive damage, and the HE shells will utterly fail against any but the lightest of cruisers.

These guns can also be effective dual-purpose guns thanks to the HE-TF shells and good gun handling. With larger aircraft, feel free to switch to the timed shells and let rip with your good accuracy and rate of fire.

Pros and cons

Pros:

• Easily capable of killing destroyers thanks to the calibre
• Adequate reload that beats many cruisers at the same tier
• Very accurate and has good shell velocity

Cons:

• Lacks the damage to threaten larger ships
• Lack of armour-piercing shells makes them weak against heavy cruisers
• Rate of fire is slow compared to similar-sized guns

History

The QF 5.25-inch naval guns were the Royal Navy's heaviest dual-purpose cannons in use during the Second World War. Fitted primarily to the King George V-class battleships, these guns proved to be effective against both other shipping and aircraft. The Royal Navy also fitted these guns to its Dido-class of light cruisers, which used them to some success while serving as convoy escorts. The guns also had the distinction of being fitted to the Royal Navy's last ever battleship, HMS Vanguard.

The 5.25-inch guns were some of the Royal Navy's first large-scale guns to be designed from the outset as dual-purpose guns (to be used against both ships and aircraft, depending on the situation). The guns were particularly noted for their ballistic performance, being able to fire more accurately and farther than its closest rivals in the French and Italian navies. This made them effective also for land bombardment, and some guns were later acquired by the British Army for coastal defence, in part due to their potent long-range firepower.

The guns were some of the last of these types to be constructed by the Royal Navy. Post-war, much of naval armament went in the way of smaller, faster cannons, as well as a larger emphasis on rockets, and later missiles.

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See also

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• reference to the article about the variant of the cannon/machine gun;
• references to approximate analogues by other nations and research trees.

External links

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