Shot out of uparmored hmmwv

[Skitrel]

Right, so I'm not actually sure whether this is a bug or not, as I'm not actually certain of what this vehicle is capable of or how it is supposed to act, but I guess this thread will find that out.

I was under the impression previously that all small arms could not shoot through the windows of the uparmored hmmwv, I've done extensive searching on the topic and can't find anything that's discussed this though, so I'm putting it forward as a potential bug, or I'm about to get ridiculed for being wrong about it altogether, one or the other.

Either way, I was shot out of one in 1 single shot by an MEC rifleman yesterday. I've previously cruised around feeling perfectly safe in these monsters taking rifle fire to the windshield and happily laughing as they bounce off. I've seen it shake of RPGs, survive 4 or 5 IEDs, and even face down a nearby gary explosion.

What are the capabilities of the vehicle supposed to be in the first place? And is a rifleman supposed to be able to shoot me out like that?