i think you should be able to throw a stone with your hand. Marksmanship skill would not come into play and you would aim at a containt rate. Damage would be consistant, something in the range of 25 damage. It should also require no skills to perform.
This would give new players a feel for marksmanship without having to get like 20 marksmanship first to be able to even see the aim bar go up.