I had a similar issue with the trigger. I haven’t quantified a time, but my perception is a quarter to half second delay between pressing the trigger, and getting the resultant burst of bullets. At first I thought it was a problem with my Saitek Profile. But I went to the Keyboard, "F" for fire, and had the same experience. I mentioned it to GhostH, but he didn't notice the difference from his side. So I chalked it up to my perception - until I read this thread.
Anyway, there's my two cents.