Destroy an enemy vehicle using the xbow - 20G

For this achievement you will need the xbow, and HE bolts for the xbow, which is unlocked by assignments.

Xbow
Sticks and stones - Win three rounds of scavenger.

HE bolts (two assignments)
Archery 101 - Get 5 kills with the Xbow, and A Good Demo Man - 5 kills with each of the following: hand grenade, underslung grenade launcher and C4.

Once you have both the Xbow and HE bolts (explosive bolts) shot at enemy vehicles. Go for jeeps, little birds, quad bikes or motorcycles. Don't waste arrows on tanks, will probably get you killed or get a kill assist.