Armor, Penetration, Damage and Aim

POSTED BY mnamestnik January 5, 2022

Overall Terms and Definitions

  • Double penetration: once a shell impacts, the flight path continues for the distance of shell caliber * 10 (100mm shell would continue for 1m), which is how it can damage internal modules and crew. The same applies for ricochets.
  • Weak spots: typically cupola, drivers hatch, lower plate
  • Two calibers rule: if the shell caliber in mm is more than twice the armor thickness in mm, normalization increases to allow penetration (unless it’s at ricochet angle)
  • Ricochet: AP/APCR 70deg or more, losing 25% of pen ability; 85 deg for HEAT, no loss of pen ability; HE no ricochet
  • Three calibers rule: if shell caliber in mm is more than 3 times that of the armor thickness in mm, it will penetrate regardless of angle

AIM

Auto-Aim

  • Tends to aim slightly below center of tank, but typically will lock onto a location on the tank (the dead center) that can be, and usually is, highly armored
  • Should only be used in specific instances such as against tanks with light armor, or to pull your gun into position on a tank (and unlocked before firing)

Pipper (the dot in the center of the reticle)

  • Ensure that armor penetration indicator is enabled in settings for your reticle
  • Red for no pen chance, orange for within range of +/- 25%, and green for “guaranteed pen”
  • Since v9.19.1, the pipper does indeed take impact angle into account when calculating the color of the pen potential
  • You might get a green indicator but it could be spaced armor so beware

Ballistic Trajectory and Line of Sight

  • Reticle takes into account ballistic trajectory, it will automatically aim a little high when you fly over a visible target, so you need to be aware of leading targets at the same height to let it adjust
  • Can affect pixel sniping based on modeling, can help to turn off vegetation in sniper mode, etc.
  • Sniper sight has the lowest point of view (where cannon is mounted), if target is behind elevation and you have difficulty placing the reticle on it, don’t use this mode
  • Arcade sight has a higher point of view for aiming (cupola), easier to aim
  • In situations where manual aiming fails, you can try auto-aim in arcade mode to see if it will help to lift the reticle up a bit further, maybe even just enough

Gunnery

  • Shot scatter, also called “2 sigma”, is dispersion of a round based on a gaussian curve that will make your shot not hit exactly where you’re aiming
  • Accuracy listed in game is for a gun at 100m. That value describes 2 standard deviations (or 2 sigma) from the center of your objective
    • Example: A gun of .32 accuracy at 100m will place 95.45% of all shots within .32m of the center of your pipper at 100m. Dispersion increases linearly with distance, so at 200m that is .64 and at 400m that is 1.28
  • The ‘reticle’ in game is the scattering circle with describes the area of 2 standard deviations from aim point. Based on normal distribution (see graph below), that means 68.3% of shots will land within the inner 50% of the reticle, 27.2% will land in the outer 50% of the reticle, and 4.5% of shots fall outside of the aiming circle.
    • Of those outside the aiming circle, 4.2% are passed through Rejection Sampling with a uniform distribution placing them in the inner/outer 50% of the reticle on an even split (supposedly)
    • The remaining .3% that would normally be completely outside the outside of the aiming circle (correlating to everything between 3 and 4 sigma in the graph below), are moved to the edge of the circle so they’re not ‘outside’, but technically they are
  • This means the final revised shot distribution for the base game, based on all the above information is such:
    • 70.4% of shots will land within the inner 50% of the reticle
    • 29.3% of shots will land within the outer 50% of the reticle
    • .3% of shots will land on the edge of your reticle
  • That said, there was a monkey wrench thrown into these dispersion calculations starting with patch 0.9.6. In this patch, Wargaming introduced zones to the reticle, with each being .2 sigma, resulting in an imaginary 10 concentric circles representing the reticle. Normally, this would mean that 16% of shots would land in the innermost zone (the bullseye/inner 10% of the reticle) based on all the math above, but Wargaming states that they changed the distribution so that only 10% fall in that zone, and the 6% loss is distributed to adjacent zones.
  • What this means is that distribution of shots, while somewhat regulated by sigma and zones, has now become non-standard and not 100% predictable since patch 0.9.6 forwards. That said, Overlord_Prime (https://docs.google.com/document/d/1au-7iJuzjSBsjhB6pLiAzMZNPxOOdrx_AFEGa6TU89Q) created a table using information collected through a game mod, to try and build a probability table using a sample size of 380k+ shots. In this example below, the ‘Exclusive’ section represents the probability of shots landing in that particular zone, whereas the ‘Cumulative’ section represents the probability of shots landing on or within a zone/radius:
  • Accuracy penalties come into play during shooting, turret rotation, vehicle movement, and vehicle rotation. Equipment, crew perks, and directives can help reduce the effect, but it will happen to some level
  • From Overlord_Prime in his Google Doc (https://docs.google.com/document/d/1au-7iJuzjSBsjhB6pLiAzMZNPxOOdrx_AFEGa6TU89Q): They did a test to determine whether some tanks have better/worse sigma dispersion (aka the “Russian Bias”), and while the results were interesting, they were also inconclusive of coming to this determination and over the course of 10,000+ shots being fired from each test vehicle, the shot placements all normalized out in the end to almost exactly mirror the expected sigma dispersion(s).

Bloom

  • Bloom determines the size of your reticle, aiming determines the decrease in reticle size over time
  • Reticle size (bloom) in WoT is calculated using hidden dispersion penalties to apply a modifier (penalty) to your dispersion (accuracy).
  • A damaged gun only affects dispersion (accuracy) of the gun and doesn’t apply a dispersion penalty the same way as everything else that is a penalty, in that it is considered a static modifier. This penalty remains until the damaged gun is fixed.
  • There are 4 dispersion penalties that can be applied at any given moment, and they are either static or dynamic (dynamic meaning they have variable values and are dependent on the rate or speed of the movement associated with their respective penalties (the faster the movement, the higher the penalty)
    • Static – Firing: the moment a shot is fired, instantaneous penalty applied to bloom
    • Dynamic – Hull Movement: any linear movement of the vehicle hull (Movementdispersion = Hullmovement x Speedkph)
    • Dynamic – Hull Traverse: any rotational movement of the vehicle hull that changes hull angle (Rotationdispersion = Hulltraverse x Traversedeg/s)
    • Dynamic – Turret Traverse: any movement of vehicle barrel that changes its position (Turretdispersion = Turrettraverse x Traversedeg/s)
  • You can acquire dispersion penalty values from something like tanks.gg since the values are hidden in-game. If you care to do the math and get the actual bloom values, you can use this following formula:

Aim Time

  • There is a formula for determining how long it will take to fully aim a shot after coming to a stop, and the following is that formula, where:
    • Dispersion_0 = the starting bloom or reticle size (obtained from Bloom formula above)
    • Dispersion_t = the dispersion the user wishes to have at a given time (for example, the fully aimed dispersion of a German gun at 0.26)
    • aimtime = the vehicle’s aimtime, listed as a stat for the tank in the garage

Unified Aim Time Formula (combining Bloom and Aim Time)

  • Different gun handling equipment modifies different statistics relevant to aim time in the formula above:
    • Aim speed increase and/or aim time reduction
      • Enhanced Gun Laying Drive
    • Dispersion penalty
      • Vertical Stabilizer
      • Improved Rotation Mechanism
    • Dispersion
      • Improved Aiming (Unit)
    • Traverse speed
      • Improved Rotation Mechanism
    • Gunner (crew) proficiency
      • Improved Ventilation

Penetration and Damage Spread

  • The only real confirmation we have on how damage and penetration spread works in WoT is from Overlord, a Wargaming staff member, who stated the following is all true (as of 2013) for both. The following points are written from the perspective of damage, but as stated can be applied to either.
  • While damage spread can vary +/- 25% (based on RNG), Wargaming doesn’t use a uniform distribution method. Similar to shot distribution, they use the standard normal distribution to calculate the value that determines how much damage is dealt. Distribution is based on the spread with the center being the average damage value listed for the gun, and this would mean that a higher weight is given to shots dealing near average/expected damage most of the time, and decreases the probability of extreme outliers.
  • Again based on information from Overlord in 2013, sigma used for spread was +/- 2.5 sigma. Shots outside of range are raised to the minimum value or lowered to the maximum. 1.24% of shots land outside the range, so that’s .62% of all shots will be at one end of the extreme (-25% roll) or the other (+25% roll)
    • As an aside, some empirical tests have shown the number to be closer to +/-3.1 sigma, but we’ll continue as if the stated 2.5 sigma is correct
  • The vast majority of your shots will land within 15% of your expected value, as you can see from this probability table:
  • Why does it feel more common to see minimum rolls over maximum rolls?
    • The two reasons for this sentiment are confirmation bias and low health vehicles. We’re more prone to remember minimum damage rolls because they’re statistically unlikely and are more memorable (i.e. frustrating) when they occur. Low health vehicles play a factor in this because you can overkill (apply more damage than HP remaining) which results in it being considered a ‘high roll’ which causes them to be removed from your mental ‘sample’.

Penetration

  • Penetration gets the +/- 25% RNG roll the same as damage, and it happened before the RNG roll is made for damage
  • Penetration value doesn’t decrease if <= 100m
  • AP/APCR penetrates obstacles but loses 25mm of pen for doing so (cars/fences)
  • Max range of a round (to have it still penetrate) is 360m-720m depending on the shell caliber
  • HEAT doesn’t lose pen at distance, but is slowest and can’t pass through obstacles
  • HE doesn’t lose pen at distance, travels almost as fast as AP, and can pass through some obstacles and screens, but takes penetration value loss when doing so (view the ammo topic for more info)
  • Examples:
    • Can shoot through obstacles (fences, destructible structures, etc.): AP/APCR/HE/HESH
    • Fire at slow/well armored tanks far away: HEAT
    • Fire at scouts at long distance: APCR
    • Enemy is paper thin: HEAT/HE/HESH

Damage

Ramming Damage

  • Collision creates spherical explosion with similar properties to that of what HE shells used to have. Strength of explosion calculated by (0.5 * combined weight * relative speed ^ 2)
  • Damage potential distributed according to weight of the two colliding vehicles relative to their combined weight (1 – individual weight / combined weight)
    • Ex. 75 ton tank rams 25 ton tank, only 25% of the explosion affects the larger tank
  • If you are about to be rammed, reduce damage taken by moving away from approaching enemy and reducing your relative speed, and point your strongest armor at them. Controlled impact perk requires you to be moving anyway to activate it (so if you have that perk you have to be moving at the moment of impact)
    • Ex. If you can aim your tracks to take the explosion impact, you’ll simply get detracked as it’s spaced armor, versus letting them hit your actual tank armor – if you’re tracked at the moment of impact, controlled impact can’t take effect

Module/Crew Damage

  • Every shell has a set module damage value based on caliber: 75mm is 100, 105mm is 150, etc.
  • Module damage values are not effected by shell type
  • Every crew member has a flat 33% chance to get knocked out from AP/APCR/HEAT, and 10% from HE – all subject to a saving throw
  • Yellow module means it has lost 50% of health/HP and thus 50% of functionality, applies to fuel tank, turret, gun, engine, ammo rack
  • Red modules are destroyed
    • Destroyed rangefinder reduces spotting range by 85%
    • Destroyed fuel tank, fire guaranteed to start
    • Destroyed engine, module HP reduced to 0, but will still move if on an decline/if you already had momentum
    • Destroyed ammo rack, vehicle destroyed if rounds are remaining in the tank
  • Saving throw: refers to the chance a module will actually take damage upon being hit. Each module has a set value for this, 100% is guaranteed to do dmg, 0% it is impossible to deal dmg:
    • Suspension: 100%
    • Engine: 45%
    • Fuel tank: 45%
    • Observation device: 45%
    • Radio: 45%
    • Turret ring: 45%
    • Gun: 33%
    • Ammunition rack: 27%

Armor

  • While armor has a thickness measured in millimeters (mm), impact angle as compared to normal axis is referred to as ‘Relative Armor’. The greater the impact angle, the more armor you have to penetrate:
  • What this results in is referred to as ‘Effective Armor Thickness’, which you can see demonstrated below:
  • Effective armor thickness calculation formula: thickness/cos(angle)
    • Ex. 150mm of armor at 50deg is actually 233mm of armor
  • Good rule of thumb is that armor at 60deg will double its effectiveness
  • Shell normalization: when an AP/APCR shell hits armor at an angle, normalization is the process whereby the shell is dragged towards normal entry angle (0 degrees) by a certain amount in order to increase its chance to penetrate.
    • For AP, normalization is 5 degrees
    • For APCR, normalization is 2 degrees
    • For HEAT/HE/HESH, there is no normalization
  • The below is an example of what that looks like:

Zero Damage Hits / Spaced Armor

  • Generally speaking, you don’t want to try to penetrate through tracks
  • Don’t be fooled by a green pipper, sometimes its spaced armor – you need to make sure you know what you’re looking at

How to Block Damage

  • KNOW YOUR TANK, KNOW THE ENEMIES’ TANKS
    • Use tanks.gg to lookup common competitive tanks
    • Use wotguru.com’s weak spot guides (https://wotguru.com/weak-spot-guides/)
    • If you can, learn about ALL tanks, weak spots, modules, crew
    • If not, learn enough about MOST to be true enough in most cases
  • If you have a rectangular turret, turn to the side to increase nominal armor thickness (maintain ricochet angle)
  • Hide the cupola, keep it behind the cover if it’s on a particular side, or turn the turret to get it there, otherwise rock a lot, move the turret around, raise the gun into the path of the cupola and swing back and forth, etc.
  • If you have good depression, use slopes to your advantage; create your own depression using hills and debris piles
  • On corners, setup a side-scrape, if possible (mid/rear mount turret), which looks like the below:
  • You can side poke if you have a mid/forward mounted gun, just tease their shots then pull out and fire once they do, but DON’T expose your drive sprocket, or ‘front wheel’ when you do (they could track you in the open and burn you down)
    • Don’t side poke a guy who is looking at you WITHOUT his having fired first on a tease
    • How to properly side poke:
  • If you have a pike nose tank (like an IS-3 or IS-7), reverse side-scrape
  • Play the bait fish, bait the enemy into firing at your hull side, but at the last minute as they fire angle towards them so as to ricochet the round off the side of the tank

Protecting Your Weak Spots

  • Gun up and wiggling to protect cupola
  • Protect lower plate, hull down, behind debris/undulations in terrain, driver’s hatch, use cover whenever possible
  • Hull rocking and turret moving to throw off enemy shots
  • And finally, face hugging, especially against bad depression tanks, forces them to shoot turret or cupola, use gun to protect cupola

Final Thoughts

Most important, to tie it all together – Situational Awareness

  • You can be penetrated from all sides, so use concealment to keep from being spotted, but when you are spotted, have a plan and put it into play IMMEDIATELY to use terrain deviations and cover to keep your flanks secure when possible
  • If you can’t use cover or terrain, KNOW YOUR ENEMIES, time your hull and turret traversing to their shots so that you have the proper angles to bounce incoming rounds while working your way to cover (once survived a 6-on-1 in a T-54 by using this method until I could get into cover and get support from my team)

Interesting Things Of Note

  • Buildings are made of two sections, if you want to get rid of the building quickly, fire HE at the center, or use HE to knock down trees
  • The reticle size in the game is incorrect, the true size is smaller than what is shown in game, so shots hitting the edge of the reticle are typically due to server desync
  • Vertical movement of the gun results in ZERO dispersion penalties

This training material was derived from many and various sources including WG wikis, forum posts, various materials drawn together by community contributors (13Disciple and Guido1212, for instance), WG training videos, and other materials such as Overlord_Prime’s Google Doc (https://docs.google.com/document/d/1au-7iJuzjSBsjhB6pLiAzMZNPxOOdrx_AFEGa6TU89Q) and the World of Tanks Game Manual (https://worldoftanks.com/dcont/fb/wot_guide/world_of_tanks_game_manual_en_com_web_8_8.pdf). As such, I am not the copyright holder of the information contained herein, but I AM the copyright holder for the information in the format in which it exists as presented on mtltemplar.com, so I exercise the right to demand that reuse of the content as it appears on my site requires my explicit permission.