Virtual Guns with Swarm Targeting?

I am thinking about implementation of hit rate time derivative metric against adaptive bots. What I see that at the beginning the circular gun is quite good against plenty of good and even top bots. But then it contaminates hit stats, i.e. adaptive bots are not hit by the circular gun anymore but other guns still have low but steadily improving hit rates. 

Hit rates can be compared only
among  the last N tics, which would somewhat mitigates this. But it has no predictive power to see the gun which would be the best in the next round.