Handle default magazines properly for items with magazine_adaptor mods (

CleverRaven#35278)

* Handle magazine_adaptor mods in magazine_default

* Fix ar15_retool_300blk ammotypes

data/json/items/gun/300BLK.json

@@ -60,24 +60,9 @@
   },
   {
     "id": "ar15_retool_300blk",
-    "copy-from": "rifle_semi",
+    "copy-from": "ar15",
     "type": "GUN",
     "name": "AR-15",
-    "//": "This is assumed to be the standard model matching the (currently not in-game) M16.",
-    "description": "This ubiquitous rifle is the forefather of M16 rifle series.  It is lightweight and accurate, but will malfunction if not properly maintained.  This one is a semi automatic civilian version.",
-    "weight": "2815 g",
-    "volume": "2 L",
-    "price": 125000,
-    "to_hit": -1,
-    "bashing": 12,
-    "material": [ "steel", "plastic" ],
-    "symbol": "(",
-    "color": "dark_gray",
-    "ammo": "300blk",
-    "dispersion": 150,
-    "durability": 7,
-    "min_cycle_recoil": 1350,
-    "default_mods": [ "retool_ar15_300blk" ],
-    "magazines": [ [ "300blk", [ "stanag30", "stanag50", "survivor223mag" ] ] ]
+    "default_mods": [ "retool_ar15_300blk" ]
   }
 ]

src/item.cpp

@@ -6662,6 +6662,16 @@ bool item::magazine_integral() const
 itype_id item::magazine_default( bool conversion ) const
 {
     if( !ammo_types( conversion ).empty() ) {
+        if( conversion ) {
+            for( const item *m : is_gun() ? gunmods() : toolmods() ) {
+                if( !m->type->mod->magazine_adaptor.empty() ) {
+                    auto mags = m->type->mod->magazine_adaptor.find( ammotype( *ammo_types( conversion ).begin() ) );
+                    if( mags != m->type->mod->magazine_adaptor.end() ) {
+                        return *( mags->second.begin() );
+                    }
+                }
+            }
+        }
         auto mag = type->magazine_default.find( ammotype( *ammo_types( conversion ).begin() ) );
         if( mag != type->magazine_default.end() ) {
             return mag->second;