Penetration and armour,
as four multipliers you can actually multiply

Two numbers set every damage conversation in this game. A head has about 40 HP. A thorax has about 85. Everything else — penetration stat, armour class, effective range, firing power — exists to decide whether a given round can move one of those two numbers to zero in one shot, two shots, or never. Start from those two figures and the rest of the table becomes readable.

The four gates a bullet passes through

A hit on an armoured target is resolved in this order: does the round penetrate at all, how much flesh damage survives the penetration, did the shot arrive inside the weapon’s effective range, and what does the gun’s firing power stat add or subtract. The gates are multiplicative, which is why a round that looks fine on paper can fail in a raid: it only has to lose one gate badly.

Gate one: class difference decides penetration and carry-over

The first digit of a penetration stat is the round’s class. The second digit controls how much flesh damage carries through the plate. Testing against the full ammunition table gives four clean bands:

The asymmetry is the whole design. Going up a class buys 90 to 98 percent; going down a class costs about 40 percent and does not get meaningfully worse as you keep descending. That is why class 3 and below ammunition has no real role against class 5 and 6 plates — it is not that the damage is slightly low, it is that the penetration roll becomes a lottery you lose most of the time.

Armour condition changes the roll, not the multiplier. A damaged plate raises the chance that a lower-class round gets through; a plate at one point of durability still blocks 30 to 40 percent of the first bullet that hits it. Zeroed armour is genuinely dead weight, but the step from 100 percent to 5 percent durability is nothing like the step from 5 percent to zero.

Gate two: range multiplies the whole shot by 0.7

Every weapon has an effective range, and outside it the target takes 70 percent of the round’s damage. This is the single most common reason a clean headshot does not drop somebody. A 47-damage 5.56 round at 70 percent delivers 33, which is short of 40, and no amount of aim fixes the arithmetic.

Range interacts with penetration in a way that is worse than it looks. Outside effective range, the chance to penetrate drops as well, so the two penalties stack: first the plate eats the round, then what survives is multiplied by 0.7. A same-class penetration outside range therefore delivers roughly 60 percent of 70 percent — a little over 40 percent of the printed flesh damage. This is why dumping a magazine into someone at 50 metres can end with them walking away.

Range cutoffs differ sharply by calibre, and this is where the ammunition table earns its keep:

• 5.56 A1 stops penetrating at 62 percent of the weapon’s effective range; A2 reaches 75 percent; M995 holds to 100 percent. On a short-barrelled 5.56 weapon with a 32-metre range, that puts the A1 cutoff at about 21 metres — well inside a normal Farm sight line.
• 5.45 BP penetrates same-class helmets at any distance at all, which is why the AK-12 keeps being recommended as an all-round gun.
• 7.62x39 holds to 100 percent and keeps penetrating to roughly 130 percent of effective range, which is why the calibre survives its recoil.
• 9x19 cuts off at 62 percent, and 9x19 7N12 versus class 5 is worse still against a weapon whose range is already short.
• .45 ACP class 4 penetrates class 4 helmets at any range — an outlier that makes the Vector .45 and M1911 relevant far past their stat block.
• 7.62x54 holds to about 200 percent of effective range, the widest window in the game, but not beyond it.

There is a second range effect worth knowing: at around 170 percent of effective range, even a higher-class small-calibre round stops penetrating pristine armour on the first shot. Bigger bullets keep working further out. This is a calibre property, not a class property, and it is the reason long-range fights on Valley reward the 7.62 platforms over the 5.56 ones.

Gate three: penetration carry-over already applied, firing power adds on top

Firing power is extra damage the weapon adds to the round, and it is the stat that separates two guns chambered for the same ammunition. The bands, measured rather than inferred:

The bonus is not free money. It is reduced by range (plus two rounds down to plus one, plus four to plus three), and it is reduced again when the round has to penetrate armour — plus six can arrive as plus four, plus eight as plus five or six depending on the round’s class. Penalties stack in diminishing fashion, so the last reduction is always smaller than the first. That ordering matters when you are deciding whether a mid-tier round plus a high-firing-power gun beats a high-tier round in a cheap gun.

Blunt damage: the consolation prize that is not a rounding error

When a round fails to penetrate, it still delivers blunt damage, and blunt damage ignores armour class entirely. It is the same number whether you are hitting a class 3 plate or a class 6 one.

• Assault rifles: 3 to 5 per round.
• Marksman rifles: 4 to 6 — an M110 with the same ammunition as a FAL does more blunt damage than the FAL does.
• SMGs: 2 to 4, the lowest band.
• Bolt actions: 4 to 6 for the M24, 9 for the SJ, 6 for the Mosin — again a firing-power consequence.

Outside effective range, blunt damage drops by one point in the 3–5 band and by two points at 6 and above. The practical upshot is that high-rate-of-fire weapons got a real buff: an MPX with class 3 ammunition against class 5 armour can bank about 40 blunt damage before the first round penetrates, which turns a hopeless matchup into a two-round finish. On a 900 RPM gun that is a fraction of a second.

Ricochet, the random term

Helmets carry a ricochet chance that is not shown as a clean percentage in the stat block. High ricochet on a fresh helmet sits around 15 percent after the season 5 changes, rising to about 20 percent once the helmet has taken damage; medium runs 4 to 6 percent; low is zero. Treat any headshot that sparks as a coin flip you did not get, not as a bug, and do not build a plan around it — but do expect it more often when shooting at damaged helmets, which is the opposite of intuition.

The season 5 changes that broke the old shortcuts

Two adjustments invalidated most of the community’s pre-patch advice at once. The first is the Mosin firing-power nerf: the gun was moved to low, which is minus seven flesh damage relative to where it sat, and that is exactly the margin that used to make a cheap bolt action a one-tap threat at range. The second is the top-tier ammunition nerf: class 7 rounds still penetrate anything in the game, but outside effective range they no longer kill a naked head in one shot — the round that used to justify a six-figure price now needs two.

The consequences, stated as instructions rather than trivia:

• Do not pay for class 7 to solve a class 6 problem. Where class 7 used to be the answer, class 6 special-purpose rounds now cover the same targets, and where class 7 is genuinely needed it takes two shots anyway.
• Same class kills inside range, does not kill outside it; one class above kills outside it. That single line explains most of the headshot complaints in the game and it is a better planning rule than any tier list.
• Class 5 and 6 helmets survived the patch better than class 4 did. If you are choosing one piece of armour to upgrade, upgrade the helmet last — or accept that it is a blunt-damage buffer, not a headshot shield.
• Expensive armour does not beat expensive ammunition. A class 6 rig costs close to a million and still dies to three rounds of top-tier rifle ammunition, or one to the head. Buy consistency in team fights, not immunity.

How to use this without memorising a table

Three questions, asked in order, cover almost every decision:

1. What class is the armour I expect? Pick a round one class above it. Not two — two is wasted money, because the carry-over is already 90 to 98 percent at plus one.
2. At what range will I actually shoot? Match the calibre to the sight line. If the answer is beyond 60 metres, 5.56 A1 is the wrong round regardless of class, and 7.62x39 or a marksman calibre is the right one.
3. What does my gun add? A high firing-power weapon can carry a mid-tier round through a same-class plate; a low firing-power weapon needs the class advantage to do the same job.

Everything else — blunt damage, ricochet, armour material — is a modifier on those three answers. Armour material in particular affects how well a plate repairs between raids and nothing else measurable; it does not change how much flesh damage gets through.