An Alternative to AC and DR

Mechanics

Lately I’ve been trying to decide if I should have attack rolls in my ruleset or not. I’ve played both ways and like auto-hit attacks for two reasons: they’re fast and missing is boring anyway. However, I recognize that the threat of a miss might encourage players to be more creative in combat and the ability to differentiate between a good fighter and a bad fighter just by looking at one number on a character sheet has some value.

But that’s a decision for another day. Were I to remove attack rolls I’d need a mechanic to represent armor in place of AC. Armor as damage reduction comes to mind and I did briefly trial it last year.

Here’s a look at the effects of DR:

Armord4 average damaged6 average damaged8 average damage
None2.53.5 4.5
DR-11.52.53.5
DR-20.751.662.625
DR-30.2511.875
DR-400.51.25

DR is absurdly powerful at the damage scales commonly used in D&D and similar games. Any more than a couple points and you’re nigh unkillable.