We had this problem for the past few years as far as I remember, 1 out of 10 30mm rounds fired from the K4 explodes but does not do any damage. I guess it can be said the these misfires are realistic but knowing that all out engines are 100% reliable, guns never jam, and nothing else ever misfires I assume this was not purposely planed.
I am really hoping this would get fixed in the near future.
thanks