Artus' Careful Shot power has the highest Attack value of all attacks of all heroes , so it is best for to equip him with the Belt of Hill Giant Strength (+1 to damage, but the item is destroyed if an attack misses) AND Hunter's Bracelet (+1 to attack roll so he is less likely to miss an attack... and destroy the Belt of Hill Giant Strength) AND Luckstone (re-roll with +4 bonus if he misses an attack, which means a chance to save the Belt.) So those three items have synergies if you put them altogether on the same hero.

Also: one of his Daily Powers, Lightning Arrow, does half damage if misses. I think if Lightning Arrow misses, the Belt of Hill Giant Strength is deactivated but NOT destroyed. So that is another reason to put the belt on Artus.

Do NOT put the Belt of Hill Giant Strength on Dragonbait as he misses too often, (which I did.)
Dragonbait kept missing and destroying the Belt.