Marksman's skill....

Erm... GM, may i noe y is tat priercing arow can be used and the monsters APPEAR to take dmg but they dont. I really hope tat u may do sth abt this as this is the skill tat deal alot of dmg.Thank you very much.(I figure out tat since i can use the skill and "numbers" have appeared above the mobs head when they get hit, so i guess this bug would be solved?)