Charting Tool

An AP (or SAP) shell that hits the target runs three checks in sequence. Each one can stop the damage.

1. Overmatch. If caliber × 14.3 is at least the armor thickness, the shell auto-penetrates regardless of impact angle. The 14.3 ratio is a hard game constant — no ship, commander, or upgrade changes it. The ladder above is the canonical Legends armor steps; the overmatch chip is your gun's threshold.
2. Ricochet. If the shell is not overmatched, impact angle decides whether it bounces. The ricochet chip shows the bounce band as min°–guaranteed° measured from the plate normal: at angles below the min the shell always bites, above the guaranteed it always bounces, and in between the bounce is probabilistic. Wider bands punish angled targets less; Yamato-class AP has 50°–65° instead of the usual 45°–60°.
3. Fuse. Once the shell penetrates, it has to travel far enough inside the ship to arm and explode. The fuse chip shows the minimum armor thickness that triggers arming — below it the shell over-penetrates (passes through without doing citadel damage). IJN improved-AP fuse drops this threshold so AP arms against thinner plates than usual.

The chart's leftmost data point is at ~1.5 km, where drag has already shaved a small amount off muzzle velocity; the muzzle AP pen chip matches the in-game spec card "AP Pen Close" value (formula at v₀, before drag). HE skips ricochet and fuse entirely — it uses a flat caliber-based pen and never bounces under normal hit geometry.