The mining laser can certainly be used as a weapon, but it does rather terrible damage compared to the bow (which makes sense as a balancing aspect)
As an alternative as a weapon, it would fire pellets for a considerable amount of damage, it would also require an HV to charge, and would be at tier with say the quantum suit. It should -also- require iridium to make.
It would do no block damage, but would do 9 hearts of damage, with about twice the range and speed of a bow, no charge up, but a 3 second cooldown (if that's even possible to code with 'tools')
Recipe for the pellets could be two advanced alloys stacked on top of each other, to make 16 rounds, up to a stack of 64. It would store 1 million EU, and spend 2.5k EU per shot.
Perhaps a sound similiar to this: http://www.youtube.com/watch?v=fTLt_6LGeLU
Something piercing and powerful sounding.