1 50cal bullet can essentially kill any unarmored vehicle if it hits the right place. 1 50cal gun can chew up any unarmored vehicle in seconds. P47's have EIGHT 50cal guns. Shouldn't they be able to make short work of the road convoy in AHII then? Whenever I go to shoot up the convoy I have to put a few hundred rounds into 1 truck to kill it. They should not be that tough should they?
The convoy's and roads got a nice new look in the latest update, but I think their damage modeling could still use a little adjusting.
Also, can we get some trains near the frontlines to shoot up too? 
The key is "hit in the right place". With any FMJ the round is going to travel straight through and unless it hits something worth while (critical engine parts, fuel tank, driver, etc), nothing is really going to become of the damage. It will literally be just a hole. However, switch that projectile over to an HE or frangible projectile and the story is altogether different because as soon as that projectile makes contact with the target then we have an area effect where a hit in the engine could kill the diver, a hit to the passenger seat could not kill the driver but disable the engine, or a hit to the cargo bed not do any other damage than to the rear axle PTO, etc, etc.
I actually take the position that it is too easy to kill convoy trucks, and M3's for that matter. Same goes for Wirblewinds, Ostwinds, M16's, and SdKfz 251's. I wish HTC would up their hardness factor about %25.