The round you load matters more than the gun you load it into. Two operators with the same rifle and different ammo are not playing the same game: one is hitting plates that stop everything, the other is going through them. Everything below is how to read that difference on the ammo chart, which holds 70 rounds across 14 calibers with the same columns for each.
The four numbers that matter
- Penetration (Pen). The round's raw penetration figure. Higher goes through more armour and keeps doing so as the plate wears down.
- Class. The armour class the chart rates the round to defeat reliably. This is what players mean by "T4 ammo" or "T5 ammo". A class-5 round is expected to beat class-5 plates and below; against class 6 expect most hits to be absorbed. The class pages list every round at or above a given class.
- Flesh damage. Damage to an unarmoured hitbox. The health system tracks seven parts — a leg or arm shot with a high-flesh round is a real injury, and high-pen rounds usually give some of this away.
- Armour damage. How much durability a hit strips from the plate. Matters in long fights: a plate at low durability stops less, which is why armour class is a threshold, not a guarantee.
Velocity is the fifth: flatter trajectory and less lead at range. It decides sniper and DMR fights more than it decides a stairwell.
Calibers, in one table's worth of words
On the current chart the ceiling by caliber looks like this — the round named is the top of its ladder by penetration:
- Class 7: 7.62×54mm (7N37) — the only round rated above class 6.
- Class 6: 7.62×51mm (M61), .338 (AP).
- Class 5: 5.56×45mm (M995), 5.45×39mm (BS), 7.62×39mm (AP), 9×39mm (7N12), 5.8×42mm (DVC12), 5.7×28mm (SS198).
- Class 4: 9×19mm (7N31), .44 (JSP).
- Class 3: 12×70mm (Armor-Piercing Slug), .45 (AP).
- Class 2: 7.62×25mm (Pst).
Read that as a map of what a weapon class can ever do. An SMG in 9×19 tops out at class 4 no matter how it is built; a 5.56 rifle reaches class 5; the marksman and sniper calibers are where class 6 and 7 live. That is also why the weapon class pages point you at the caliber before the gun.
The trade-off
Within a caliber the ladder is nearly always the same shape: the cheapest round has the most flesh damage and the least penetration, the top round the reverse. Against AI in light gear or a player's limbs, the cheap round kills faster. Against a plate it bounces. The usual answer is to carry both — a magazine of the high-pen round for the fight you expect and a cheaper stack for the rest — and since Season 4 you can mix ammo types inside one magazine in a preset build.
Every weapon has a best-ammo page that calls out the top of each column for its caliber, so you do not have to read the whole chart per gun.
Match the round to the tier
Difficulty tiers decide who you meet and, from Season 7, what anyone can load: T4 and below in Normal, T5 and below in Lockdown, Forbidden uncapped. In Normal, then, class 4 is the ceiling for everyone and the class-4 page is the whole shopping list. Season 7 also removes the T5/T6 penetration RNG, so the class rating becomes closer to a hard rule than a probability.
What the chart does not tell you
Prices — the market moves too fast for a versioned chart, so this site does not print them. Fragmentation — not recorded. Whether a specific plate will stop a specific round at a specific durability — the game does not publish its penetration formula, and the armour calculator is labelled as a model for exactly that reason. The chart tells you the ceiling and the ladder; the raid tells you the rest.