So, In the past I have always treated spells like magic missile as autohits. It's how I understand the rules, but i have a new house rule enacting a concentration check (DC SL+5) for any spell cast in combat since my magic users want to roll anyway. My question is have I been adjudicating the "no roll" spells correctly? Am I missing a step with magic missile (atm: player: "I cast" me:"roll damage"
Spells with Saving Throw: None and Spell Resistance: No, and which do not specify an attack roll or other contest to determine their effects, and which are cast by a character not subject to an arcane spell failure chance nor any other sort of spell failure chance come into effect without any any roll on the caster's part to determine their effects, usually. You are not missing any steps in the casting of magic missile at least as regards its dealing damage.