BT-7M

This page is about the Soviet light tank BT-7M. For other versions, see BT-7 (Family).

BT-7M

BT-7

BT-7M

BT-7

USSR

I Rank

Battle rating:

AB	RB	SB
2.0	2.0	2.0

Class:

Light tank

Research:5 900

Purchase:6 300

Description

The BT-7M is a rank I Soviet light tank with a battle rating of 2.0 (AB/RB/SB). It was introduced in Update "Ixwa Strike".

General info

Survivability and armour

Armourfront / side / back

Hull20 / 15 / 13

Turret15 / 15 / 13

Crew3 people

Visibility84 %

The armour of the BT-7M features noteable improvements over the preceding BT-7. The frontal hull and the frontal half of the side hull are now 20mm, which makes it more effective at deflecting bullets/autocannon shells when angled and/or at a distance. Vehicles such as M16 MGMC and Flakpanzer 38 now might be somewhat less threatening due to your increased hull armour. The turret, however, keeps the same armour, which is 13-15mm all-round. This is inadequate to stop HMG bullets and any AP or even HE shells at any distance. It can only resist rifle caliber bullets from vehicles like Light AA Mk I. Overall, despite the thickened hull, the BT-7M is still protected in a light tank style and should not risk to take any hits. 

The post-penetration survivability is just as poor as the other BT models. The only 3 crew are closely packed, with the gunner and commander right next to each other in the turret, and the driver directly in front of them. Any penetrating shots, regardless of explosive or solid, will have no issue taking out most/all of them. The weak armour also leads to the crew being vulnerable to over pressure damage. Vehicles with large caliber guns like the Sturmpanzer II and M4A3 (105) will easily destroy the BT-7M with a single HE shell. The only positive aspect is the large fuel tanks at the rear hull sides, outside the engine. These fuel tanks protect the engine by absorbing poorly aimed shots although they might be set aflame, thus keeping the BT-7M driveable for a few more seconds. 

Armour type:

• Rolled homogeneous armour (hull, turret)

Armour	Front (Slope angle)	Sides	Rear	Roof
Hull	20 mm (18°) Upper plate 15 mm (61°) Middle plate 20 mm Lower plate	20 mm Forward 15 mm + 4 mm Rearward	10-13 mm	10 mm Roof 4 mm Radiator grilles
Turret	15 mm Turret front 15 mm Gun mantlet	15 mm Forward 13 mm Rearward	13 mm	10 mm

Notes:

• Suspension wheels, tracks and torsion bars are 15 mm thick.
• Belly armour is 6 mm thick.

Mobility

The BT-7M's mobility is just as classic as the other BT tanks. Although it is heavier than the earlier BT, at 14.2 tons, it is now driven by a powerful engine with a whopping 500hp, giving it a power/weight ratio of ~35. This allows it to pick up speed extremely fast and reach its top speed relatively easy. On hard surfaces like dirt/concrete road it can easily hit ~50 km/h, while on softer terrain it is usually ~40 km/h. This makes the BT-7M one of the fastest tracked vehicles in game, allowing it to get to any position quickly.

The reverse speed, at 11 km/h, is just enough to reverse you back into cover if you did not peek out far enough, if too far it will still be dangerously slow. The hull traverse is somewhat sluggish when the tank is stationary, often needing a short forward/backward jerk before turning. It does not lose a significant amount of speed when turning at high speed. 

Speedforward / back

AB69 / 12 km/h

RB and SB63 / 11 km/h

Number of gears3 forward

1 back

Weight14.7 t

Engine power

AB954 hp

RB and SB500 hp

Power-to-weight ratio

AB64.9 hp/t

RB and SB34.0 hp/t

Game Mode	Max Speed (km/h)		Weight (tons)	Engine power (horsepower)		Power-to-weight ratio (hp/ton)
	Forward	Reverse		Stock	Upgraded	Stock	Upgraded
Arcade	69	12	14.7	775	954	52.72	64.9
Realistic	63	11		442	500	30.07	34.01

Modifications and economy

Repair costBasic → Reference

AB249 → 320

RB286 → 368

SB359 → 462

Total cost of modifications5 940

4 500

Talisman cost410

Crew training1 800

Experts6 300

Aces75

Research Aces135 000

Reward for battleAB / RB / SB

20 / 20 / 30 %

106 / 106 / 106 %

Modifications

Mobility	Protection	Firepower
Tracks Research: 300 Cost: 230 55 Suspension Research: 330 Cost: 250 60 Brake System Research: 330 Cost: 250 60 Filters Research: 500 Cost: 380 90 Transmission Research: 640 Cost: 480 115 Engine Research: 640 Cost: 480 115	Improved Parts Research: 300 Cost: 230 55 Improved FPE Research: 330 Cost: 250 60 Crew Replenishment Research: 500 Cost: 380 90	Horizontal Drive Research: 300 Cost: 230 55 45mm_AP_1942_ammo_pack Research: 300 Cost: 230 55 Adjustment of Fire Research: 330 Cost: 250 60 Elevation Mechanism Research: 500 Cost: 380 90 Artillery Support Research: 640 Cost: 480 115

Armaments

Main armament

The BT-7M is equipped with the common 45mm 20-K cannon found on most early war Soviet tanks. The cannon is very beginner friendly, as it has a rather fast reload speed of ~3 seconds, allowing you to quickly fire more shots if the first shot failed to hit/one-shot. The velocity is adequate and the trajectory not too curved, meaning distant/moving targets are too worth a try.

The gun depression of -5° is worse than that of the BT-5 so now you will not be able to perform hull-down at certain spots, or you must expose more of your hull to do so. But since the BT-7M is not a large tank, it can still use this gun depression in some hilly terrains. The turret rotation can be a bit slow especially when you need to target tanks at diferent directions, but traversing the hull will generally help.

Note: you do not have a shoulder stabiliser like some other early war tanks, so if you suddenly encounter an enemy while driving at high speed it might be a good idea to just keep driving until you are in cover, instead of instinctively breaking to a stop and try to aim. Most vertically stabilised tanks like Pz.II will certainly complete the targeting process before you and shoot before you do which can be fatal. 

45 mm 20-K cannon

Ammunition188 rounds

Reloadbasic crew → aces

3.8 → 2.9 s

Vertical guidance-5° / 20°

45 mm 20-K					Turret rotation speed (°/s)					Reloading rate (seconds)
Mode	Capacity	Vertical	Horizontal	Stabilizer	Stock	Upgraded	Full	Expert	Aced	Stock	Full	Expert	Aced
Arcade	188	-5°/+20°	±180°	N/A	15.2	21.1	25.6	28.3	30.1	3.77	3.33	3.07	2.90
Realistic					9.5	11.2	13.6	15.0	16.0

Ammunition

• The default round is an excellent APHEBC: the BR-240. It has a miximum penetration of 70mm, although not the best for similar calibers it can still frontally penetrate almost all light and medium tanks effortlessly. It packs 29g explosive filler meaning its explosion shrapnel are usually enough to knock out most if not all crew inside common tanks like Pz.III, Chi-Ha, Crusader, etc. Against larger tanks like LVT(A), more shots might be required to finish the target. 

• The researchable BR-240SP is a solid AP that trades the explosive filler with ~3mm more penetration, which is not an impressive improvement. This is usually not the ideal round, since most of the targets can be penetrated by the APHEBC just fine, and the ones that cannot be penetrated will also be tough for the solid AP. The only chance might be when you take the BT-7m to a higher BR battle and face targets with armour thickness between 70-73mm. For example, with add-on armour the frontal hull of the Pz.IV F2 becomes 50+20=70mm. The APHEBC, with 70mm maximum penetration, can struggle if not being completely unable to penetrate at point blank range, but the AP can go though it easier with its extra 3mm penetration. 

Penetration statistics
Ammunition	Type of warhead	Penetration @ 0° Angle of Attack (mm)
		10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
BR-240	APHEBC	70	68	59	50	42	35
BR-240SP	AP	73	71	62	52	44	37

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%
BR-240	APHEBC	760	1.43	1.2	9	29.26	48°	63°	71°
BR-240SP	AP	757	1.43	N/A	N/A	N/A	47°	60°	65°

Ammo racks

Ammo racks of the BT-7 (identical).

Full ammo	1st rack empty	2nd rack empty	3rd rack empty	4th rack empty	5th rack empty	6th rack empty	7th rack empty
188	174 (+14)	162 (+26)	147 (+41)	135 (+53)	123 (+65)	108 (+80)	89 (+99)
8th rack empty	9th rack empty	10th rack empty	11th rack empty	12th rack empty	13th rack empty	Visual discrepancy
73 (+115)	57 (+131)	41 (+147)	25 (+163)	13 (+175)	1 (+187)	No

Notes:

• Racks disappear after you've fired all shells in the rack.
• Turret empty: 147 (+41) shells.
• Turret and side racks empty: 89 (+99) shells.

Machine guns

7.62 mm DT machine gun (coaxial)

Ammunition1 890 rounds

Belt capacity63 rounds

Reloadbasic crew → aces

10.4 → 8.0 s

Fire rate600 shots/min

7.62 mm DT
Mount	Capacity (Belt)	Fire rate	Vertical	Horizontal
Coaxial	1,890 (63)	600	N/A	N/A

Usage in battles

Describe the tactics of playing in the vehicle, the features of using vehicles in the team and advice on tactics. Refrain from creating a "guide" - do not impose a single point of view but instead give the reader food for thought. Describe the most dangerous enemies and give recommendations on fighting them. If necessary, note the specifics of the game in different modes (AB, RB, SB).

Pros and cons

Summarise and briefly evaluate the vehicle in terms of its characteristics and combat effectiveness. Mark its pros and cons in a bulleted list. Try not to use more than 6 points for each of the characteristics. Avoid using categorical definitions such as "bad", "good" and the like - use substitutions with softer forms such as "inadequate" and "effective".

Pros:

• Upgraded engine compared to the previous BT-7
• Fast-firing gun
• Exceptionally nimble, being able to turn its hull very quickly

Cons:

• Sits at a higher BR than the previous BT-7
• Armour remains thin, with heavy machine guns being able to penetrate and knock out crew members
• Only 3 crew members
• Oversteers at high speed, leading to it spinning out and/or drifting and loosing its speed

History

The BT-7M was an improved version of the Soviet BT-7 light tank developed before the Second World War. The main improvement was in terms of the powerplant, and at the time it was built no other tank in the world could reach the same speeds.

Development

Development of a version of the BT-7 light tank began in the Soviet Union in 1938 with the construction of four prototypes at the Kharkov Locomotive Plant called the BT-8, which used a V12 diesel engine which was developed from the Hispano-Suiza 12Y aircraft engine. After the BT-8 was tested against the BT-7 it was determined to continue its development which resulted in the production version, designated BT-7M.

Design

The BT-7M had the 500 horsepower V12 engine which was actually chosen partly due to greater fuel efficiency. The hull was reinforced with braces and some of the fuel storage was removed due to the higher fuel efficiency of the engine. The BT-7M’s engine also proved to be much safer in that it caught on fire much less often when hit by enemy fire. The BT-7M was proven to have a top speed of 62 km/h on tracks and 86 km/h with just wheels. Other than these changes, the BT-7M was fairly similar to the regular BT-7.

Production and Service

The BT-7M entered production in 1939, replacing all earlier BT-7 variants on production lines. It was the last BT-7 variant produced with production lasting until 1941. Approximately 788 BT-7M tanks were built during that time period, being superseded on production lines by the T-34 medium tank. The BT-7M did end up seeing some combat during the Great Patriotic War.

Media

Skins

• Skins and camouflages for the BT-7M from live.warthunder.com.

Videos

First 10: BT-7M - Orangefan

See also

Links to the articles on the War Thunder Wiki that you think will be useful for the reader, for example:

• reference to the series of the vehicles;
• links to approximate analogues of other nations and research trees.

External links

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