Merge pull request #65852 from TimPollard/gun_random_capacity_rework

Using default mags to calculate max capacity for guns with random ammo

src/item_group.cpp

@@ -425,9 +425,22 @@ void Item_modifier::modify( item &new_item, const std::string &context ) const
     }
 
     int max_capacity = -1;
-    if( charges.first != -1 && charges.second == -1 && new_item.is_magazine() ) {
-        const int max_ammo = new_item.ammo_capacity( item_controller->find_template(
-                                 new_item.ammo_default() )->ammo->type );
+
+    if( charges.first != -1 && charges.second == -1 && ( new_item.is_magazine() ||
+            new_item.uses_magazine() ) ) {
+        int max_ammo = 0;
+
+        if( new_item.is_magazine() ) {
+            // Get the ammo capacity of the new item itself
+            max_ammo = new_item.ammo_capacity( item_controller->find_template(
+                                                   new_item.ammo_default() )->ammo->type );
+        } else if( !new_item.magazine_default().is_null() ) {
+            // Get the capacity of the item's default magazine
+            max_ammo = item_controller->find_template( new_item.magazine_default() )->magazine->capacity;
+        }
+        // Don't change the ammo capacity from 0 if the item isn't a magazine
+        // and doesn't have a default magazine with a capacity
+
         if( max_ammo > 0 ) {
             max_capacity = max_ammo;
         }