"Well, not a Rolemaster level chart, but yes, a chart. Basically, you have the AC numbers running along the top and the various weapons running down as the column. When attacking, you find the row with the appropriate weapon, then run across to the AC number and that shows you what you need to roll to hit. Thus, swords work really well against unarmoured folks, but not well at all against plate mail. A mace, OTOH, is the reverse."

-- Armor Class in "Spellcraft & Swordplay"