Due to the mechanics of piercing damage, piercing bullets (such as Meteor Shot) will only hit enemies one time, even if all bullets connect. The remaining rounds can still rebound on objects behind the target (having not caused damage) and hit the target a second time.
Exploding Bullets can be an alternative for their area damage, although care should be taken not to hurt oneself. The combined knockback of the ammunition and weapon can be effective for holding off enemies in early Hardmode.
Cursed Bullets will help more in PvP, because Crystal Bullets only hit players with their primary projectiles, since players become momentarily invulnerable when damaged, so the shards won't have any effect. The greater primary damage of Cursed Bullets and the Cursed Infernodebuff will deal more damage in this case.