oops, my remark about the 5 round legality applies to Canada. I did not notice your location at that time. I can't really say what the laws are in California....but by what I read they are every bit as bad and contorted as ours. But reading the whole thread it looks like we have figured out why you are missing each 5th round.
We had a couple guys using tracer during our recent milsurp shoot when trying to hit the furthest target. The guys thought it was pretty cool. I have just picked up 800+ rounds of 8mm tracer. I'll have to organise a night shoot this spring.