real quick: there are two variables to tactics, speed and focus. Run and gun is a fast, outside tactic. So, to counter it, you need a fast outside defense. The two best suited to this are FCP and 1-3-1.
FCP- forces lots of turnovers, but will give up many baskets if they can beat the press. Risky and tires your guys out for offense
1-3-1- Fast and helps contest outside shots, but gives up ALOT of rebounds.
Solution? 3-2, if you are good enough. Helps preserve rebounds while providing outside defense. IMO, 1-3-1 loses a lot of rebounds and doesn't give a lot more OD, in one case just two sublevels, while bringing down my RB 6 sublevels. So, if you think you can run a 3-2. If you think you need to, run a 1-3-1. And if your guys have terrific stamina, run a FCP.
Just MHO.