ghostcrawler wrote:
Killing Machine is a "ppm" now or a proc per minute. That means it will proc 5 times a minute with 5 ranks, depending on your weapon speed. We generally use ppm when we do not want players to gravitate towards faster weapons with the sole purpose of improving proc rates.
Killing Machine now is based on autoattack hits, not crits. Overall the random element will decrease, but it won't greatly benefit faster weapons. It will still benefit dual wield, just not as much.
http://forums.worldofwarcraft.com/thread.html?topicId=14287259120&pageNo=1&sid=1#6
It has a set number of max procs, regardles of whether you DW or 2h. I also think OHs cannot proc it, but I can't find that GC post.