100 mm/70 SM-5-1 (100 mm)

SM-5-1 on Chapayev

Description

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Vehicles equipped with this weapon

• Chapayev
• Mikhail Kutuzov
• Shcherbakov
• Sverdlov
• Zheleznyakov

General info

The 100 mm/70 SM-5-1 100 mm naval weapon system is the first Soviet "modern" 100 mm weapon system in the game. It is comparable to MLE model 53 in terms of use, practicality, and overall handling. Different from the past WW2 100 mm, the SM-5-1 features an autoloader, enhanced targeting, and better ammunition. The SM-5-1 is essentially the smaller brother of the 130 mm/58 SM-2-1. It shares the exact same uses but with reduced performance due to the reduced calibre. This weapon system is particularly useful as either a secondary high calibre artillery or as primary AAA defense. It has a significantly reduced rate of fire per cannon compared to the MLE Model 53 (~60 RPM vs ~15 RPM) but since the turret is dual mount, the rate of fire of the SM-5-1 equals half of the MLE Model 53's. While it may seem that the SM-5-1 is overall inferior due to the reduced performance in targeting speed, elevation angles, and rate of fire per turret, this is countered with substantially more weapon mounts per ship. So far in game, the Chapayev and Sverdlov can achieve ~120 RPM and ~180 RPM respectively due to the substantially more weapon mounts compared to the Lübeck and Köln F220 which stay around ~120 RPM.

Available ammunition

The SM-5-1 has access to ammunition already seen before in similar weapon systems. These are: OF-55 HE, ZS-55 HE-TF, F-55 HE-F and ZS-55R AA-VT. The wide variety of ammunition gives a vast variety of usages for this weapon system. As expected, the OF-55 HE offers the most powerful explosive filler for the system that can cause significant damage to lightly armoured vehicles due to the rate of fire. However, it barely has penetration to deal with armour (24 mm of armour penetration). This is where the F-55 HE-F comes in handy. As an HE round with base fuse, it does not explode immediately on contact, similar to SAPBC. This round has 73 mm of penetration and can deal easier with armoured targets. However, the explosive filler is reduces by couple grams. While this does not significantly affect the overall performance of the round, this should be kept in mind. Finally, the ZS-55 has more than 2 kg of TNT equivalent, while the ZS-55R has 1.2 kg of TNT equivalent. At first sight, the time fused version looks better in performance due to the increased filler and barely increased speed, but it is much harder to aim and accurately hit an enemy aircraft as the round has to land very close to the aircraft to cause significant damage while the HE-VT can just be fired with higher chances of dealing damage without the hassle of manually changing and setting the time fuse. Both rounds are a major threat when it comes to dealing with enemy aircraft, it is up to the player to decide which one to pick and use.

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
100 mm OF-55 HE	HE	24	24	24	24	24	24
100 mm ZS-55 AA	HE-TF	26	26	26	26	26	26
100 mm F-55 HE-F	HE	73	63	54	46	40	34
100 mm ZS-55R AA-VT	HE-VT	17	17	17	17	17	17

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%
100 mm OF-55 HE	HE	1,000	15.6	0	0.1	1.94	79°	80°	81°
100 mm ZS-55 AA	HE-TF	1,000	15.6	0	0.1	2.07	79°	80°	81°
100 mm F-55 HE-F	HE	1,000	15.6	0.035	5	1.77	79°	80°	81°

Proximity-fused shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile mass (kg)	Fuse delay (s)	Fuse sensitivity (mm)	Arming distance (m)	Trigger radius (m)	Explosive mass (TNT equivalent) (kg)	Ricochet
									0%	50%	100%
100 mm ZS-55R AA-VT	HE-VT	995	15.9	0	0.1	270	15	1.26	79°	80°	81°

Comparison with analogues

• 100 mm/55 MLE model 53 - While very similar, there are differences primarily in targeting speed and rate of fire. The SM-5-1 is able to hold continuous firing for longer with a vast variety of ammunition while the MLE model 53 can only utilize two type of rounds. The overall performance of the rounds are better in terms of explosive filler and the fact the MLE model 53 lacks any sort of armour piercing ammunition gives the upper hand to the SM-5-1. The huge speed difference makes the SM-5-1 easier to aim and use at longer ranges (995+ m/s vs 855 m/s). However, the MLE Model 53 has significantly better targeting speeds and a slightly better vertical aiming angle (85° vs 90°).

• 4.5 inch/45 QF Mark V - The 4.5 inch Mark V is the closest system to the SM-5-1 performance wise. While it has a faster rate of fire (20 RPM vs 15 RPM) it has slightly reduced targeting speed (17°/s vs 18°/s). Ammunition wise, while both have nearly the exact same ammunition, the SM-5-1 ammunition have much better explosive filler, penetration (with exception of the SAPBC round) and speed (995+ m/s vs 746 m/s) despite being a smaller calibre.

Usage in battles

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Pros and cons

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Pros:

Cons:

History

This gun was designed specifically for the Chapayev class (Project 68) cruisers. Manufactured between 1948 and 1955 with a total of 150 weapons being built for the five Chapaev class and twenty Sverdlov class (Project 68bis) cruisers.

These guns were controlled by the "Zenit-68bis A" Fire Control System which was used to control both these guns and the smaller AA guns. This system included a "Yakor'" radar and a SPN-500 radar system. The final targeting data was given by TsAS-1 and PKU-1 control systems. Any 100 mm (3.9") turret could provide firing data should the central computer be knocked out.

The SM-5 mounting was developed specifically for the Chapayev class cruisers and entered service in 1949. It was a twin mounting with local fire control as backup for the central fire control system of the ship. The SM-5-1 mountings were used on the first for Sverdlov class, later Sverdlov class used the SM-5-1bis. The Chapayev used the SM-5.

The mounting was cross-level stabilized up to -20/+20 degrees of roll using a Jenny-type coupling which was automatically controlled from a central location using the remote control system D-5S. In 1949 a BL-127 quadruple mount was designed, but this was not approved for production.

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External links

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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)