45 mm/46 21-K (45 mm)

Description

The 45 mm/46 21-K is a Soviet anti-aircraft gun derived from the 20-K tank gun. It is equipped on a number of Soviet coastal and bluewater vessels.

Vehicles equipped with this weapon

• Frunze
• Kirov
• Krasny Kavkaz
• Krasny Krym
• Maxim Gorky
• MBK-161 early
• Moskva
• Voroshilov

General info

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Available ammunition

• OR-73A HET - Stock HE shell, has low explosive mass and should be replaced quickly
• O-240 HE - Researchable HE shell, has more than 3 times the explosive mass of the stock but very low velocity, effective at boats in close-range
• BR-240 - APHE shell, useful against armoured targets like armoured gunboats and turrets that HE shells can't penetrate
• F-73 - Base-fuze HE shell, effectively acts like an APHE shell with larger explosive mass, is quite effective at dealing damage against ship modules as it penetrates the hull

Penetration statistics
Ammunition	Type of warhead	Penetration @ 0° Angle of Attack (mm)
		100 m	1,000 m	2,000 m	3,000 m	4,000 m	5,000 m
OR-73A HET	HE	3	3	3	3	3	3
O-240 HE	HE	5	5	5	5	5	5
BR-240	APHE	75	58	48	41	36	32
F-73	HE with base fuze	21	16	14	11	10	9

Shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile Mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive Mass (TNT equivalent) (g)	Ricochet
							0%	50%	100%
OR-73A HET	HE	760	1.41	0	0.1	56.98	79°	80°	81°
O-240 HE	HE	335	2.14	0	0.1	181.72	79°	80°	81°
BR-240	APHE	760	1.42	1	1.5	27.72	47°	60°	65°
F-73	HE	760	1.41	1.5	0.1	113.96	79°	80°	81°

Comparison with analogues

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Usage in battles

Much like in real life, the 21-K is horrible at its intended role, anti-aircraft. Its low rate of fire means it is only effective at hitting aircraft when massed, like on Maxim Gorky. On ships with few mounts like Frunze, the 21-K is essentially useless at shooting down aircraft, but it can be used as a weapon against small boats, where its HE shells can be effective at destroying them.

Pros and cons

Pros:

• Can destroy aircraft in one hit
• Somewhat effective at fighting small boats with HE and base-fused HE shells

Cons:

• Terrible anti-aircraft ability due to low rate of fire

History

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Media

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See also

• 20-K
• 45 mm/68 21-KM - Variant with longer barrel and higher muzzle velocity
• 3.7 cm SK C/30 - German anti-aircraft gun with similar rate of fire

External links

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• topic on the official game forum;
• other literature.

USSR naval cannons
20 mm	ShVAK
25 mm	2M-3
30 mm	AK-230 · 30 mm/54 AK-630 · 30 mm/54 AK-630M · BP "Plamya"
37 mm	37 mm/67 70-K · V-11
45 mm	45 mm/46 21-K · 45 mm/68 21-KM · 45 mm/89 SM-20-ZIF · 45 mm/89 SM-21-ZIF
57 mm	AK-725
75 mm	75 mm/50 Canet patt.1892
76 mm	34-K · 39-K · 76 mm/60 AK-176M · AK-726 · D-56TS · F-34 · Lender AA gun, pattern 1914/15
85 mm	85 mm/52 92-K · 85 mm/54.6 ZIS-C-53 · 90-K
100 mm	100 mm/56 B-34 · 100 mm/70 SM-5-1 · Minizini
102 mm	Pattern 1911
120 mm	120 mm/50 pattern 1905
130 mm	130 mm/55 pattern 1913 · 130 mm/58 SM-2-1 · B-13
152 mm	152 mm/57 B-38
180 mm	180 mm/57 B-1-P · 180 mm/60 B-1-K
305 mm	12-inch/52 pattern 1907 · 305 mm/54 B-50
356 mm	14-inch/52 pattern 1913 (356 mm)
	Foreign:
40 mm	2pdr QF Mk.IIc (Britain) · Skoda (Czechoslovakia)
47 mm	3 pdr QF Hotchkiss (Britain)
76 mm	76 mm/40 Ansaldo mod.1917 (Italy)
88 mm	SK C/30 (Germany)
120 mm	120 mm/50 Mk.4 Bofors M1924 (Sweden) · 120 mm/50 O.T.O. Mod.1933 (Italy)
152 mm	152/53 mm O.T.O. Mod.1929 (Italy)
320 mm	320 mm/44 Ansaldo model 1934 (Italy)