Ammo that penetrates class 3 armour
39 rounds13 calibers39 rounds are rated at class 3 or higher on the patch 1.0.0.142.19 chart — 14 exactly at class 3, the rest above it. Against class 3 plates these are the rounds that go through rather than get eaten.
Best per caliber
Every round rated class 3+
Not yet recorded for this patch: Price
What the class rating means
Armour in Arena Breakout: Infinite is class 1 to 6. The chart rates each round by the highest class it reliably penetrates; a round rated class 3 is expected to go through class 3 plates and below, and to be stopped or heavily reduced by anything higher. Durability matters too — a plate that has already taken hits stops less.
To see what a given weapon can load, open its best-ammo page from the weapons index; the full chart with every column is the ammunition index, and the plates themselves are under armour.