How to make bowmaster on pvp better?

Attack range, for the most part, doesn't matter in PvP.

What does matter is Battle ATK. Equips such as Larson's set adds battle ATK, which increases PvP damage.

I'm not experienced with BMs, but I think what most BMs do is set down your scarecrow close to a mob of people, jump over to the side, and spam inferno.

It's not really the class that sucks; I've seen every class do well in PvP except for Buccs, who really do suck.

I've even seen a bucc do well.