Well, it depends on the ammo and the gun being used. The m2 hmg has a much longer barrel than the m82 sniper rifle (45 inches vs 29 inches, respectively), resulting in more velocity and more penetration on its ammunition. I will therefore only consider the m2 hmg in my answer below. It is almost as old as the m2hb itself. It completely depends on the car and the armor being used thereof.
Armor penetration of 50 bmg vs. other rounds. However, like all rifle and machine-gun bullets, the m8 api is a relatively light projectile (40 g). I believe it was first introduced during ww2, as a further development of the m2 ap bullet. Can also sustain side blasts of up to 120 kg tnt. At close range, i. Good quality hot-formed armor and quality modern cad applications is used to create 3d models. 7mm m8 api bullet has been around for a very long time. I think it cam go through about 2 inches before it begins to get stuck.
Cal ammo designed for anti-armor use: the. 100 yds or less, a 50 cal can penetrate normal vertical armor plate of roughly 20 mm or a bit more than 3 quarter of an inch. Then, you will need an rpg to get further penetration.