An article from Tibianews, published 21. october 2007, suggests that the attack rate for Infernal Bolts is 43. Power Bolts with 40 attack (cost only 7 gp per shot) and Assassin Stars with 65 attack (cost 33 gp per shot) render infernal bolts an unnecessary expensive ammunition. If you can't buy Infernal Bolts for less than 20 gp you should prefer hunting with Assassin Stars, you can wear a shield and deal about 15% more average damage than Infernal Bolts. The only situation where you should pay more is when you really need the higher range (6 sqm with Royal Crossbow instead of 4).
Click Here to Show/Hide Spoiler Information
Spoiler warning:Quest and/or game spoiling details follow.