I'm trying to break 75% accuracy on Left 4 Dead 2. I can consistently get about 60% accuracy with either of the automatic shotguns, but when I try with the M-16, my percentage drops to the high 40s.
Assuming that my shooting habits don't change from firearm to firearm, the only thing that I can think of that would cause this drop is the fact that the shotgun's slower firing rate means that every common infected is guaranteed to get one and only one round. With the M-16, it's very likely that a particular bullet will kill the zed, but by the time I realize that it's dead, I've fired once or twice more.
My question is: Do bullets fired at dead or dying zombies* count against your accuracy rating? This has a follow-on question: What about bullets fired at zombies that a teammate has also been firing at? If your teammate kills the zombie, does your accuracy decrease for those bullets you fired at it?
(*And before you say it, yes, I know that all zombies are dead)