A question for Harry Potter fans...

I admit I am not a big fan of the Potterverse so I am not well versed in the intricacies of the seven books. I have seen the six movies so I have some idea what is going on. One question plagues me about the whole thing:

Why doesn't anyone just shoot Voldemort?

I mean really, with all the bad latin and spell casting going around I would think you could unload a couple rounds into the bad guy's head before he got his first wand-wave off. Is there some sort of mystic code preventing wizards from being practical? Is it just a British thing and only American children would consider the advantages of packing heat? Are sorcerers incapable of figuring out how a trigger mechanism works?

I am no great fan of Jim Butcher's Dresden Files but at least the principle character often tries to have a smoke wagon on hand in the event his power reserves are low or he is without wand and staff. Harry Dresden is practical like that.

I just think the Death Eaters would be a lot less scary in the face of Armalites and AKs, thassall...