The Japan Steel Works 120mm L/44 smoothbore gun used by the STC-1 and the TKX-0002 prototypes of the Type 90 main battle tank actually had superior accuracy and higher armor penetration than the Rheinmetall 120mm smoothbore gun as proven during tests conducted by the JSDF in 1983 The JSW 120mm smoothbore gun was based on an experimental 135mm smoothbore gun developed by Daikin Industries for the STC-1 prototype in 1979.

This massive 135mm gun had APFSDS ammunition capable of extremely high muzzle velocities exceeding 2,000 m/s.

It was actually much easier to conduct transmission maintenance and repair on the Panther and Tiger II when compared to the Tiger I.

This is because removing the transmission on the Panther and Tiger II did not require the removal of the turret. These tanks had a maintenance hatch above the crew compartment in the hull which can be opened to give access to the transmission.

Afterwards you just need to remove the radio equipment and then you could pull the transmission out of the tank with the help of a crane truck.

The Hedgehog armor (Igelpanzerung) is a special roof armor used by the Panzerhaübitze 2000 155mm self-propelled gun and the Schützenpanzer Puma infantry fighting vehicle designed to defeat shaped charge cluster bombs which target the thin roof armor of tanks.





Anti-tank cluster bombs deploy hundreds of shaped charge bomblets over armored vehicle formations and convoys.

These bomblets are very small in size but could penetrate over 100mm of armor, more than enough to pierce through the 20-40mm roof armor of modern main battle tanks.

Ever wonder why are the T-64 and the T-72's side skirts intended to be flipped open in combat?

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These are actually a special type of side skirts called "gill armor" which is designed to protect the tank's hull sides from shaped charge weapons.

These are flipped open outwards to provide a much greater stand-off distance when hit by HEAT shells and anti-tank weapons within the 70° frontal arc of the tank.

I updated my Abrams turret composite armor illustrations based on the armor of the M1150 ABV and other information I got from some experts.

It turns out the only times the physical thickness of the turret armor was increased was on the M1A1 in 1985 and on the M1A2 SEPv3 in 2020.





The downgraded composite armor of export Abrams models likely only reverted back to the original BRL-1 NERA arrays which used rubber.

However, the M1A1s sold to the Australians has the same third generation composite armor used by American Abrams tanks, just without the DU armor

The Stillbrew armor of the Chieftain tank was actually very effective against APFSDS rounds

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Testing of the armor prototypes in 1985 showed that it can easily defeat the new L23 Tungsten alloy 120mm APFSDS round of the Challenger 1 even at a distance of just 1,000 meters.



At that distance, the L23 APFSDS can penetrate 455mm of rolled homogeneous steel armor.

They also tested the Stillbrew against the 3BK-14 125mm HEAT-FS shell which can penetrate 450mm and the armor was also able to defeat it.

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Stillbrew Armor:

~460mm vs APFSDS
~500mm vs HEAT

The hull composite armor of the T-14 Armata is actually only ~650mm thick and mainly consisted of three steel armor plates sloped at 40°

However, it also uses special Silicon Carbide nanoceramic armor inserts which can be equal to almost 200% of steel armor against APFSDS rounds

Nanoceramic armor achieves this higher effectiveness by having more compact nano scale grains which makes them up to 70% harder than conventional ceramics.

Speaking of perfect stuff, the most perfect autoloader ever made (in my opinion) was the Meggitt compact autoloader system designed for the M1 Abrams in the late 2000s.

This autoloader didn't occupy much space and a fourth crew member could still be seated inside the turret.

It had an extremely high 34 round ammunition capacity which is only 2 rounds less than the 36 rounds stored inside the turret racks of the M1 Abrams.

The conveyor-belt was also modular and the tanks could be quickly replenished just by swapping the conveyors through the roof.

The T-90 series of main battle tanks actually had an improved turret composite armor that was twice as effective as the original reflector plate arrays used by the T-72B.

The new design used a 50mm thick RHA plates with two layers of rubber sheets and high hardness steel plates.

This improved double reflector plate NERA design was developed for the Object 188 (T-90 prototype) in the late 1980s and would have also been used by other future Soviet tanks like the Object 187.

Although its really annoying to hear Brits talk about the "superior accuracy" of their 120mm rifled guns, APFSDS rounds fired from rifled gun barrels do achieve some 20% higher accuracy over APFSDS rounds fired from smoothbore guns. Now we know APFSDS projectiles designed to be fired from rifled gun barrels do feature slipping driving bands to prevent them from getting spun quickly by the rifling.

Aside from keeping their weight less than 40* tons, one of the reasons why the T-64/72/80/90 tanks only have one very slow reverse gear is because their transmission is designed to be very easy to maintain and repair in the field without the help of heavy engineering vehicles.

*The reason they used an extremely compact transmission was really because of the T-64.

The Soviet high command wanted the new tank to be just slightly heavier than the 36 ton T-55, so Kharkov did everything to make the T-64 only weight 37 tons.

The Israeli Merkava III & IV main battle tanks actually use NxRA and SLERA armor arrays.

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Non-eXplosive Reactive Armor and Self-Limiting Explosive Reactive Armor are two types of reactive armor that bridge the gap between NERA which uses rubber and ERA which uses explosives.

Non-eXplosive Reactive Armor (NERA supposedly stands for Non-Energetic Reactive Armor) uses reactive polymers combined with gas generating chemical compounds to provide a highly energetic reaction that would destabilize the shaped charge jet.

In 2003, the US military acquired four T-84 main battle tanks from Ukraine for testing and evaluation.

They were shocked to discover that the M829A2 120mm DU APFSDS of the M1 Abrams couldn't penetrate the hull armor of the T-84 when its covered with the Kontakt-5 ERA.





"but wasn't the M829A2 already designed to defeat the Kontakt-5?"

During the development of the M829A2 in the early 1990s, the US was only able to test the new round using T-72M1, T-72A and T-72B tanks equipped with the Kontakt-5 as well as a single T-80U mod. 1989 from the UK.

After realizing how extremely difficult it is to cast turrets with ceramic balls inside it, the Soviets decided to use a completely different turret armor on production models of the T-64.

To save time, they settled for a design that had a steel-aluminum-steel composite array.



This unique turret armor actually functions using the same compression-decompression mechanism as the steel-textolite-steel hull armor to defeat shaped charges.

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When piercing through thick steel armor, the tip of the shaped charge jet experiences extremely high pressures.

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The polymer cell turret armor of the T-80U was probably the most advanced composite armor developed by the Soviet Union during the Cold War.

It was even proven to have superior protection over Western tanks including the M1A1HA Abrams with Depleted Uranium armor in the 1990s.



Invented by the Institute of Hydrodynamics of the Siberian branch of the Soviet Academy of Sciences, the polymer cell composite armor was designed to use the hydraulic shockwave effects of liquid filled containers to defeat shaped charges and kinetic energy penetrators.

Some of you might be wondering why did the Russians keep using the vertical NERA arrays of the T-72B on the T-90 so I'm going to explain the reasoning behind it.

One of the disadvantages of this configuration is that the NERA arrays could be bypassed when hit angles beyond 30°. However, at such angles the much thinner turret side armor is also exposed to the enemy, so the tank still becomes vulnerable even if the composite armor in the turret cheeks doesn't get compromised when hit beyond the frontal arc.

If any of you are wondering what are these welded boxes on the sides of some Leopard 2 tanks, its actually a turret ammunition loading port that was found on early variants of the Leopard 2 but was later removed in the Leopard 2A4 in 1984.

These turret side ports were originally used for throwing out casings on older tanks like the Leopard 1.

Back then it was necessary to throw out spent casings after every 4-5 shots, as these would fill up the brass catcher and make it more difficult to load another round.

The Shtora APS used by Russian tanks works by using two infrared dazzlers to jam the guidance systems of SACLOS ATGMs.

SACLOS guidance systems use a flare sensor to track the missile's rocket motor (or infrared beacon in the case of the BGM-71 TOW). The flare sensor detects if the missile is diverting from the center of the sight crosshairs and automatically sends command signals to the missile (via wire or radio) to adjust its flight trajectory and get it back at the center of the sights.