How do I damage vehicles with primary weapons to unlock the railgun?

[DarkWolf]

Armor piercing damage only does 1 damage, so I'll have to shoot them 500 times with that

[Space Cat]

Use underbarrel grenade launcher on a rifle, use the AP rounds.

[Nemesis2k7]

use armor piercing rounds

[DarkWolf]

Originally posted by Nemesis:

use armor piercing rounds

They deal, like, 1 damage per shot. It's super slow.

[Space Cat]

Underbarrel 40MM AP