Enhancements as per issue tracking sheet

module/models/weapon.mjs

@@ -13,10 +13,8 @@ export default class OathHammerWeapon extends foundry.abstract.TypeDataModel {
       required: true, initial: "common", choices: SYSTEM.WEAPON_PROFICIENCY_GROUPS
     })
 
-    // Damage: melee = Might rank + damageMod dice; bows = baseDice (fixed, no Might)
-    // usesMight=true  → formula displayed as "M+2", "M-1", etc.
-    // usesMight=false → formula displayed as e.g. "6" (fixed dice for bows)
-    schema.usesMight = new fields.BooleanField({ required: true, initial: true })
+    // Damage: melee/throwing = Might rank + damageMod dice; bows = baseDice (fixed, no Might)
+    // usesMight is now derived from proficiencyGroup (see getter below)
     schema.damageMod = new fields.NumberField({ ...requiredInteger, initial: 0, min: -4, max: 16 })
 
     // AP (Armor Penetration): penalty imposed on armor/defense rolls
@@ -71,9 +69,16 @@ export default class OathHammerWeapon extends foundry.abstract.TypeDataModel {
       const map = { 0: "common", 1: "uncommon", 2: "rare", 3: "very-rare", 4: "legendary", 5: "legendary", 6: "legendary" }
       source.rarity = map[source.rarity] ?? "common"
     }
+    // Remove legacy usesMight field — now derived from proficiencyGroup
+    delete source.usesMight
     return super.migrateData(source)
   }
 
+  /** Derived: only bows skip Might for damage. Throwing weapons keep Might (arm strength). */
+  get usesMight() {
+    return this.proficiencyGroup !== "bows"
+  }
+
   /**
    * Human-readable damage formula for display, e.g. "M+2", "M-1", "6"
    */