https://www.youtube.com/watch?v=hcSI9sn3-b4&feature=youtu.be Here is a video for it.

I have the same problem! I have windows 7 though not 8. Its frustrating since I really can't go any where with zombies. I added a video to show the problem on my end. Going to post a separate thing for the axe hitting multiple times too. With each weapon pulled out they just stop working entirely. I tried shooting all of them, not even the sounds of the pin striking in an empty chamber work.

I have seen it too with clothes and stuff. Items are invisible is all.