Uhm, no, that is not what I meant
It does not have to have such absurd rate of fire, 1 shot per second is perfectly enough - but the key is high accuracy and high damage here. Basically a blob turret with quick projectiles. It would be better than beam because the player in fact COULD avoid it if he really wanted, but that would require some skill and lots of determination - while avoiding beams is just hoping for random miss, really...
Or to make it even simplier - take a Shivan Light Laser from a Cain, and increase its damage to say, 80 dmg per shot. This weapon is already fast and accurate enough. It just lacks damage. Possible to avoid? Kinda hard but yes. Would you carelessly pound the Cain without actually thinking about its defences? I doubt. On the other hand, would it be possible to destroy it with a fighter? Yes, but it would require more time and more skill, and in the same time, less luck than you need when facing beams.