what is the best tactic i can use against run and gun?
Good perimeter defense. ;)
Seriously, if you know your opponent is going to play R&G, it makes sense to try to counter this with a 3-2 zone (assuming all else is equal). Or, if his perimeter shooting is much better than your perimeter defense
and you you have a massive rebounding skill advantage, a 1-3-1 may be appropriate.
One of the best ways to counter any offense is to attack the weak sector(s) of your opponent's defense.
