Ammo chart
What goes through what. Pick your caliber, pick what they're wearing, and load the round that gets the job done.
Classes go weakest to toughest, left to right. Not sure? Leave it on Any and just compare the rounds.
The chart
Stopped by is the first armor class the round can't get through cleanly. Each bar is one class, weakest on the left: goes through (more than 8 hits in 10 on fresh armor), magdump only (a full mag in the same spot, maybe), pointless. Speed is muzzle velocity in metres a second. Accuracy is how much the round helps or hurts your gun's. Gun wear is how much faster it wears your weapon out: −15% is a little, −100% chews through it, so bring a repair kit. In Buy from, the rank is the one you need with that vendor before they'll sell it.
Ammo stats and the penetration chart from the Gray Zone Warfare wiki, written by its editors. The chart rates rounds at normal fighting distances; they lose punch further out. A round the chart doesn't have yet goes by its own wiki page (“from its wiki page”). Not affiliated with MADFINGER Games.