How does the armor penetration work in metro royale, a west lvl4 has +80 and a west lvl6 has +220. W

How does the armor penetration work in metro royale, a west lvl4 has +80 and a west lvl6 has +220. What effect has it on the damage (if any at all) when shooting normal ammo (armor penetration at 75) and high explosive ammo (armor penetration at 300)???
Was this page helpful?