diff --git a/data/json/effects_on_condition/item_eocs.json b/data/json/effects_on_condition/item_eocs.json
index 758fd0151b6b2..7a5131429d88b 100644
--- a/data/json/effects_on_condition/item_eocs.json
+++ b/data/json/effects_on_condition/item_eocs.json
@@ -15,7 +15,7 @@
     "type": "effect_on_condition",
     "id": "get_m4_carbine",
     "global": true,
-    "effect": { "u_spawn_item": "modular_m4_carbine" }
+    "effect": { "u_spawn_item": "m4_carbine", "use_item_group": true }
   },
   {
     "id": "EOC_vitrified_doll_talk",
diff --git a/data/json/furniture_and_terrain/furniture-graves.json b/data/json/furniture_and_terrain/furniture-graves.json
index 1269a1b717b08..b98996fcaa15d 100644
--- a/data/json/furniture_and_terrain/furniture-graves.json
+++ b/data/json/furniture_and_terrain/furniture-graves.json
@@ -109,7 +109,7 @@
     "flags": [ "EASY_DECONSTRUCT", "TRANSPARENT", "MOUNTABLE" ],
     "deconstruct": {
       "items": [
-        { "item": "modular_m4_carbine", "count": 1, "charges": 0, "variant": "modular_m4a1" },
+        { "group": "modular_m4a1", "count": 1, "charges": 0 },
         { "item": "helmet_army", "count": 1, "damage": [ 0, 3 ] },
         { "item": "boots_combat", "count": [ 0, 1 ], "damage": [ 0, 3 ] }
       ]
@@ -120,7 +120,7 @@
       "sound": "thump.",
       "sound_fail": "whack.",
       "items": [
-        { "item": "modular_m4_carbine", "count": 1, "charges": 0, "variant": "modular_m4a1" },
+        { "group": "modular_m4a1", "count": 1, "charges": 0 },
         { "item": "helmet_army", "count": 1, "damage": [ 0, 3 ] },
         { "item": "boots_combat", "count": [ 0, 1 ], "damage": [ 0, 3 ] }
       ]
diff --git a/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/223.json b/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/223.json
index fd6c92d6f08d6..8f760dfa1b87d 100644
--- a/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/223.json
+++ b/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/223.json
@@ -44,7 +44,7 @@
     "id": "nested_m4_carbine_no_ammo",
     "type": "item_group",
     "subtype": "collection",
-    "items": [ { "item": "modular_m4_carbine" }, { "group": "stanag_mags", "count": [ 1, 3 ] } ]
+    "items": [ { "group": "modular_m4a1" }, { "group": "stanag_mags", "count": [ 1, 3 ] } ]
   },
   {
     "id": "nested_m27_assault_rifle_no_ammo",
diff --git a/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/police_armory.json b/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/police_armory.json
index 85f7c20ab1115..bc0fd0595ee96 100644
--- a/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/police_armory.json
+++ b/data/json/itemgroups/Weapons_Mods_Ammo/arsenal/police_armory.json
@@ -1259,9 +1259,9 @@
     "//": "1-3 rifles of one type",
     "subtype": "collection",
     "entries": [
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "contents-item": "red_dot_sight" },
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "contents-item": "red_dot_sight", "prob": 50 },
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "contents-item": "red_dot_sight", "prob": 25 }
+      { "group": "modular_m4a1", "contents-item": "red_dot_sight" },
+      { "group": "modular_m4a1", "contents-item": "red_dot_sight", "prob": 50 },
+      { "group": "modular_m4a1", "contents-item": "red_dot_sight", "prob": 25 }
     ]
   },
   {
@@ -1270,19 +1270,9 @@
     "//": "1-3 rifles of one type",
     "subtype": "collection",
     "entries": [
-      { "item": "modular_m4_carbine", "variant": "m4_cqbr", "contents-item": [ "red_dot_sight", "suppressor" ] },
-      {
-        "item": "modular_m4_carbine",
-        "variant": "m4_cqbr",
-        "contents-item": [ "red_dot_sight", "suppressor" ],
-        "prob": 50
-      },
-      {
-        "item": "modular_m4_carbine",
-        "variant": "m4_cqbr",
-        "contents-item": [ "red_dot_sight", "suppressor" ],
-        "prob": 25
-      }
+      { "group": "m4_cqbr", "contents-item": [ "red_dot_sight", "suppressor" ] },
+      { "group": "m4_cqbr", "contents-item": [ "red_dot_sight", "suppressor" ], "prob": 50 },
+      { "group": "m4_cqbr", "contents-item": [ "red_dot_sight", "suppressor" ], "prob": 25 }
     ]
   },
   {
diff --git a/data/json/itemgroups/Weapons_Mods_Ammo/conversions/conversion_guns.json b/data/json/itemgroups/Weapons_Mods_Ammo/conversions/conversion_guns.json
index 2c822b49664da..ab0920cfddcc3 100644
--- a/data/json/itemgroups/Weapons_Mods_Ammo/conversions/conversion_guns.json
+++ b/data/json/itemgroups/Weapons_Mods_Ammo/conversions/conversion_guns.json
@@ -1,14 +1,16 @@
 [
+  {
+    "id": "m4_carbine",
+    "type": "item_group",
+    "subtype": "collection",
+    "entries": [ { "group": "modular_m4a1", "contents-item": [ "retool_ar15_223rem_medium" ] } ]
+  },
   {
     "id": "m4_cqbr",
     "type": "item_group",
     "subtype": "collection",
     "entries": [
-      {
-        "item": "modular_m4_carbine",
-        "variant": "m4_cqbr",
-        "contents-item": [ "pistol_grip", "retool_ar15_223rem_short", "suppressor", "adjustable_stock" ]
-      }
+      { "group": "m4_cqbr", "contents-item": [ "pistol_grip", "retool_ar15_223rem_short", "suppressor", "adjustable_stock" ] }
     ]
   },
   {
diff --git a/data/json/itemgroups/Weapons_Mods_Ammo/guns.json b/data/json/itemgroups/Weapons_Mods_Ammo/guns.json
index 39869fd2488d3..4720953774c43 100644
--- a/data/json/itemgroups/Weapons_Mods_Ammo/guns.json
+++ b/data/json/itemgroups/Weapons_Mods_Ammo/guns.json
@@ -462,7 +462,7 @@
       { "item": "fn_fal_semi", "variant": "fal_dsa", "prob": 40 },
       { "item": "hk_g3", "prob": 40 },
       { "item": "m1918", "prob": 30 },
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 45 },
+      { "group": "modular_m4a1", "prob": 45 },
       { "item": "m14ebr", "prob": 15 },
       { "item": "arx160", "prob": 10 },
       { "item": "modular_m16_auto_rifle", "variant": "modular_acr", "prob": 25 },
@@ -844,16 +844,14 @@
         "prob": 40
       },
       {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
+        "group": "modular_m4a1",
         "ammo-item": "556_mk318",
         "charges": [ 0, 30 ],
         "contents-item": "shoulder_strap",
         "prob": 8
       },
       {
-        "item": "modular_m4_carbine",
-        "variant": "m4_cqbr",
+        "group": "modular_m4a1",
         "ammo-item": "556_mk318",
         "charges": [ 0, 30 ],
         "contents-item": "shoulder_strap",
@@ -918,16 +916,14 @@
       { "group": "ar15_223short", "ammo-item": "223", "charges": 30, "contents-item": "shoulder_strap", "prob": 70 },
       { "group": "ar15_223long", "ammo-item": "223", "charges": 30, "contents-item": "shoulder_strap", "prob": 40 },
       {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
+        "group": "modular_m4a1",
         "ammo-item": "556_mk318",
         "charges": 30,
         "contents-item": "shoulder_strap",
         "prob": 8
       },
       {
-        "item": "modular_m4_carbine",
-        "variant": "m4_cqbr",
+        "group": "modular_m4a1",
         "ammo-item": "556_mk318",
         "charges": 30,
         "contents-item": "shoulder_strap",
@@ -1028,8 +1024,7 @@
       {
         "collection": [
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556_mk318",
             "charges": [ 0, 30 ],
             "contents-item": "shoulder_strap",
@@ -1046,8 +1041,7 @@
       {
         "collection": [
           {
-            "item": "modular_m4_carbine",
-            "variant": "m4_cqbr",
+            "group": "m4_cqbr",
             "ammo-item": "556_mk318",
             "charges": [ 0, 30 ],
             "contents-item": "shoulder_strap",
@@ -1375,8 +1369,7 @@
       {
         "collection": [
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556_mk318",
             "charges": [ 0, 30 ],
             "contents-item": "shoulder_strap",
@@ -1393,8 +1386,7 @@
       {
         "collection": [
           {
-            "item": "modular_m4_carbine",
-            "variant": "m4_cqbr",
+            "group": "m4_cqbr",
             "ammo-item": "556_mk318",
             "charges": [ 0, 30 ],
             "contents-item": "shoulder_strap",
diff --git a/data/json/itemgroups/Weapons_Mods_Ammo/nested_guns.json b/data/json/itemgroups/Weapons_Mods_Ammo/nested_guns.json
index 8ec01b6c6a098..4cd11529bef3a 100644
--- a/data/json/itemgroups/Weapons_Mods_Ammo/nested_guns.json
+++ b/data/json/itemgroups/Weapons_Mods_Ammo/nested_guns.json
@@ -1594,7 +1594,7 @@
     "subtype": "collection",
     "ammo": 100,
     "entries": [
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "charges": [ 0, 30 ] },
+      { "group": "modular_m4a1", "charges": [ 0, 30 ] },
       { "item": "stanag30" },
       { "item": "stanag30", "prob": 50 },
       { "group": "on_hand_223" }
diff --git a/data/json/itemgroups/defense_mode.json b/data/json/itemgroups/defense_mode.json
index 535ab10385922..3c155924dff1f 100644
--- a/data/json/itemgroups/defense_mode.json
+++ b/data/json/itemgroups/defense_mode.json
@@ -35,7 +35,7 @@
       { "item": "remington_870" },
       { "item": "browning_blr" },
       { "item": "ak47" },
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1" },
+      { "group": "m4_carbine" },
       { "item": "savage_111f" },
       { "item": "hk_g3" },
       { "item": "hk_g80" },
diff --git a/data/json/itemgroups/military.json b/data/json/itemgroups/military.json
index 90907c3c4ef44..0d2eb629d7a52 100644
--- a/data/json/itemgroups/military.json
+++ b/data/json/itemgroups/military.json
@@ -4,13 +4,7 @@
     "id": "military_standard_assault_rifles",
     "subtype": "distribution",
     "entries": [
-      {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
-        "prob": 88,
-        "charges": [ 0, 30 ],
-        "contents-group": "issued_carbine_mods"
-      },
+      { "group": "modular_m4a1", "prob": 88, "charges": [ 0, 30 ], "contents-group": "issued_carbine_mods" },
       {
         "item": "modular_m27_assault_rifle",
         "variant": "modular_m27iar",
@@ -32,7 +26,7 @@
     "type": "item_group",
     "id": "military_grenadier_assault_rifles",
     "subtype": "distribution",
-    "entries": [ { "item": "modular_m4_carbine", "contents-group": "issued_grenadier_mods", "prob": 100, "charges": [ 0, 30 ] } ]
+    "entries": [ { "group": "modular_m4a1", "contents-group": "issued_grenadier_mods", "prob": 100, "charges": [ 0, 30 ] } ]
   },
   {
     "id": "armor_plates",
@@ -638,7 +632,7 @@
       { "item": "20x66_slug", "prob": 4 },
       { "item": "m9", "variant": "m9", "prob": 6 },
       { "item": "usp_45", "prob": 6 },
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 7 },
+      { "group": "modular_m4a1", "prob": 7 },
       { "group": "m4_cqbr", "prob": 1 },
       { "item": "modular_m16a4", "prob": 5 },
       { "item": "modular_m16_auto_rifle", "variant": "modular_m16a3", "prob": 1 },
diff --git a/data/json/items/gun/223.json b/data/json/items/gun/223.json
index a9b7679b574a9..c2f80b038a95f 100644
--- a/data/json/items/gun/223.json
+++ b/data/json/items/gun/223.json
@@ -361,7 +361,6 @@
     "min_cycle_recoil": 1350,
     "weapon_category": [ "AUTOMATIC_RIFLES" ],
     "modes": [ [ "DEFAULT", "semi-auto", 1 ], [ "AUTO", "auto", 4 ] ],
-    "default_mods": [ "retool_ar15_223rem_medium" ],
     "valid_mod_locations": [ [ "bore", 1 ], [ "grip", 1 ], [ "mechanism", 2 ], [ "sling", 1 ], [ "stock accessory", 2 ], [ "stock", 1 ] ],
     "flags": [ "NO_TURRET" ],
     "//2": "This should be removed once vehicle turrets are capable of mounting guns with mods attached. As it stands, trying to mount this style of weapon would require the player to remove the conversion kit, thus rendering it unusable anyhow.",
diff --git a/data/json/mapgen/military/mil_base/mil_base_z0.json b/data/json/mapgen/military/mil_base/mil_base_z0.json
index 8993eb0f3f461..60252726963dc 100644
--- a/data/json/mapgen/military/mil_base/mil_base_z0.json
+++ b/data/json/mapgen/military/mil_base/mil_base_z0.json
@@ -767,15 +767,7 @@
         { "item": "m203", "x": 10, "y": 11, "chance": 75, "repeat": 5 },
         { "item": "mgl", "x": 10, "y": 11, "chance": 75, "repeat": 3 },
         { "item": "40x46mm_m433", "x": 10, "y": 12, "chance": 75, "repeat": 20 },
-        {
-          "item": "modular_m4_carbine",
-          "variant": "modular_m4a1",
-          "x": 12,
-          "y": [ 9, 11 ],
-          "magazine": 100,
-          "chance": 75,
-          "repeat": 30
-        },
+        { "group": "modular_m4a1", "x": 12, "y": [ 9, 11 ], "magazine": 100, "chance": 75, "repeat": 30 },
         {
           "item": "modular_m27_assault_rifle",
           "variant": "modular_m27iar",
@@ -789,15 +781,7 @@
         { "item": "stanag30", "x": 12, "y": 12, "chance": 75, "repeat": 80 },
         { "item": "stanag50", "x": 12, "y": 12, "chance": 75, "repeat": 20 },
         { "item": "556", "x": 14, "y": [ 9, 12 ], "chance": 75, "repeat": 150 },
-        {
-          "item": "modular_m4_carbine",
-          "variant": "modular_m4a1",
-          "x": 16,
-          "y": [ 9, 11 ],
-          "magazine": 100,
-          "chance": 75,
-          "repeat": 36
-        },
+        { "group": "modular_m4a1", "x": 16, "y": [ 9, 11 ], "magazine": 100, "chance": 75, "repeat": 36 },
         { "item": "stanag30", "x": 16, "y": 12, "chance": 75, "repeat": 100 },
         { "item": "556", "x": 18, "y": [ 9, 12 ], "chance": 75, "repeat": 150 },
         { "item": "m249", "x": 20, "y": 9, "chance": 75, "repeat": 6 },
diff --git a/data/json/monsterdrops/feral_humans.json b/data/json/monsterdrops/feral_humans.json
index a914900fb2b84..5addd8cbb7c72 100644
--- a/data/json/monsterdrops/feral_humans.json
+++ b/data/json/monsterdrops/feral_humans.json
@@ -656,7 +656,7 @@
     "magazine": 100,
     "ammo": 10,
     "id": "feral_autogun",
-    "items": [ [ "modular_m4_carbine", 500 ], { "group": "modular_ar15", "prob": 500 } ]
+    "items": [ { "group": "modular_m4a1", "prob": 500 }, { "group": "modular_ar15", "prob": 500 } ]
   },
   {
     "type": "item_group",
diff --git a/data/json/npcs/NC_ARMY.json b/data/json/npcs/NC_ARMY.json
index 3212db7ffc0b1..86c3851a0a57f 100644
--- a/data/json/npcs/NC_ARMY.json
+++ b/data/json/npcs/NC_ARMY.json
@@ -163,11 +163,7 @@
     "type": "item_group",
     "id": "NC_ARMY_rifle",
     "subtype": "distribution",
-    "entries": [
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 50 },
-      { "item": "m14ebr", "prob": 35 },
-      { "item": "m249", "prob": 20 }
-    ]
+    "entries": [ { "group": "modular_m4a1", "prob": 50 }, { "item": "m14ebr", "prob": 35 }, { "item": "m249", "prob": 20 } ]
   },
   {
     "type": "item_group",
diff --git a/data/json/npcs/NC_ARSONIST.json b/data/json/npcs/NC_ARSONIST.json
index 8f90653b4ac5f..a31d3856f8978 100644
--- a/data/json/npcs/NC_ARSONIST.json
+++ b/data/json/npcs/NC_ARSONIST.json
@@ -195,11 +195,7 @@
     "type": "item_group",
     "id": "NC_ARSONIST_rifle",
     "subtype": "distribution",
-    "entries": [
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 35 },
-      { "item": "m1a", "prob": 35 },
-      { "item": "ak47", "prob": 35 }
-    ]
+    "entries": [ { "group": "modular_m4a1", "prob": 35 }, { "item": "m1a", "prob": 35 }, { "item": "ak47", "prob": 35 } ]
   },
   {
     "type": "item_group",
diff --git a/data/json/npcs/NC_OPS.json b/data/json/npcs/NC_OPS.json
index d737a3d49d819..b5e90dec4b368 100644
--- a/data/json/npcs/NC_OPS.json
+++ b/data/json/npcs/NC_OPS.json
@@ -136,7 +136,13 @@
   {
     "type": "item_group",
     "id": "NC_OPS_rifle",
-    "items": [ [ "modular_m4_carbine", 50 ], [ "m14ebr", 35 ], [ "m249", 20 ], [ "modular_m27_assault_rifle", 50 ], [ "M24", 35 ] ]
+    "items": [
+      { "group": "modular_m4a1", "prob": 50 },
+      [ "m14ebr", 35 ],
+      [ "m249", 20 ],
+      [ "modular_m27_assault_rifle", 50 ],
+      [ "M24", 35 ]
+    ]
   },
   {
     "type": "item_group",
diff --git a/data/json/npcs/NC_SOLDIER.json b/data/json/npcs/NC_SOLDIER.json
index fdc1ac1de9a8d..f46ada8f7151f 100644
--- a/data/json/npcs/NC_SOLDIER.json
+++ b/data/json/npcs/NC_SOLDIER.json
@@ -121,13 +121,13 @@
     "type": "item_group",
     "id": "NC_SOLDIER_rifle",
     "subtype": "distribution",
-    "entries": [ { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 90 }, { "item": "m14ebr", "prob": 10 } ]
+    "entries": [ { "group": "modular_m4a1", "prob": 90 }, { "item": "m14ebr", "prob": 10 } ]
   },
   {
     "type": "item_group",
     "id": "NC_SOLDIER_weapon_random",
     "subtype": "distribution",
-    "entries": [ { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 35 } ]
+    "entries": [ { "group": "modular_m4a1", "prob": 35 } ]
   },
   {
     "type": "item_group",
diff --git a/data/json/npcs/refugee_center/surface_visitors/NPC_scavenger_mercenary.json b/data/json/npcs/refugee_center/surface_visitors/NPC_scavenger_mercenary.json
index 3407fa34403d4..9696a13910029 100644
--- a/data/json/npcs/refugee_center/surface_visitors/NPC_scavenger_mercenary.json
+++ b/data/json/npcs/refugee_center/surface_visitors/NPC_scavenger_mercenary.json
@@ -72,8 +72,7 @@
     "subtype": "collection",
     "items": [
       {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
+        "group": "modular_m4a1",
         "ammo-item": "556",
         "charges": 30,
         "contents-item": [ "shoulder_strap", "holo_sight", "suppressor" ]
diff --git a/data/json/npcs/robofac/robofac_ancilla_npcs/NC_ANCILLA_GRUNT.json b/data/json/npcs/robofac/robofac_ancilla_npcs/NC_ANCILLA_GRUNT.json
index 385f8f2d39429..2cc2f89a1c4c5 100644
--- a/data/json/npcs/robofac/robofac_ancilla_npcs/NC_ANCILLA_GRUNT.json
+++ b/data/json/npcs/robofac/robofac_ancilla_npcs/NC_ANCILLA_GRUNT.json
@@ -57,14 +57,6 @@
     "type": "item_group",
     "id": "NC_ANCILLA_GRUNT_wield",
     "subtype": "collection",
-    "items": [
-      {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
-        "ammo-item": "556",
-        "charges": 30,
-        "contents-item": [ "shoulder_strap", "suppressor" ]
-      }
-    ]
+    "items": [ { "group": "modular_m4a1", "ammo-item": "556", "charges": 30, "contents-item": [ "shoulder_strap", "suppressor" ] } ]
   }
 ]
diff --git a/data/json/professions.json b/data/json/professions.json
index 2d9ecdc0b8d32..48bde57815190 100644
--- a/data/json/professions.json
+++ b/data/json/professions.json
@@ -1540,8 +1540,7 @@
           { "item": "ear_plugs", "custom-flags": [ "no_auto_equip" ] },
           { "item": "knife_combat", "container-item": "sheath" },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "holo_sight" ]
@@ -1758,8 +1757,7 @@
           { "item": "ear_plugs", "custom-flags": [ "no_auto_equip" ] },
           { "item": "knife_combat_army", "variant": "m9bayonet", "container-item": "sheath" },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556_mk318",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "holo_sight" ]
@@ -2024,13 +2022,7 @@
           { "item": "wristwatch" },
           { "item": "bracelet_friendship" },
           { "item": "knife_combat", "container-item": "sheath" },
-          {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
-            "ammo-item": "556",
-            "charges": 30,
-            "contents-item": "shoulder_strap"
-          },
+          { "group": "modular_m4a1", "ammo-item": "556", "charges": 30, "contents-item": "shoulder_strap" },
           { "item": "stanag30", "ammo-item": "556", "charges": 30 },
           { "item": "stanag30", "ammo-item": "556", "charges": 30 },
           { "item": "stanag30", "ammo-item": "556", "charges": 30 },
@@ -5026,12 +5018,7 @@
           { "item": "water_clean", "container-item": "canteen" },
           { "item": "ear_plugs", "custom-flags": [ "no_auto_equip" ] },
           { "item": "knife_combat_army", "variant": "m9bayonet", "container-item": "sheath" },
-          {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
-            "ammo-item": "556",
-            "contents-item": "shoulder_strap"
-          },
+          { "group": "modular_m4a1", "ammo-item": "556", "contents-item": "shoulder_strap" },
           { "group": "charged_two_way_radio" },
           { "item": "chestrig", "contents-group": "army_mags_m4" }
         ]
@@ -6198,8 +6185,7 @@
             "contents-item": [ "shoulder_strap_simple", "holo_sight" ]
           },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556_mk318",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "holo_sight" ]
@@ -6623,8 +6609,7 @@
           { "item": "stethoscope", "custom-flags": [ "no_auto_equip" ] },
           { "item": "knife_combat_army", "variant": "m9bayonet", "container-item": "sheath" },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556_mk262",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "holo_sight" ]
diff --git a/data/json/vehicles/helicopters.json b/data/json/vehicles/helicopters.json
index ab4e0245ac87b..505194e8bc2df 100644
--- a/data/json/vehicles/helicopters.json
+++ b/data/json/vehicles/helicopters.json
@@ -1056,15 +1056,7 @@
       { "x": -9, "y": -1, "chance": 7, "items": [ "rucksack" ] },
       { "x": -8, "y": -1, "chance": 5, "items": [ "m9" ] },
       { "x": -7, "y": -2, "chance": 5, "items": [ "223" ] },
-      {
-        "x": -7,
-        "y": -2,
-        "chance": 5,
-        "magazine": 90,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -7, "y": -2, "chance": 5, "magazine": 90, "ammo": 70, "group": "modular_m4a1" },
       { "x": -7, "y": -2, "chance": 7, "items": [ "EMPbomb" ] },
       { "x": -7, "y": -2, "chance": 15, "items": [ "mask_gas" ] },
       { "x": -7, "y": -2, "chance": 7, "items": [ "flashlight" ], "ammo": 100 },
@@ -1255,15 +1247,7 @@
       { "x": -9, "y": -1, "chance": 7, "items": [ "rucksack" ] },
       { "x": -8, "y": -1, "chance": 5, "items": [ "m9" ] },
       { "x": -7, "y": -2, "chance": 5, "items": [ "223" ] },
-      {
-        "x": -7,
-        "y": -2,
-        "chance": 5,
-        "magazine": 90,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -7, "y": -2, "chance": 5, "magazine": 90, "ammo": 70, "group": "modular_m4a1" },
       { "x": -7, "y": -2, "chance": 7, "items": [ "EMPbomb" ] },
       { "x": -7, "y": -2, "chance": 15, "items": [ "mask_gas" ] },
       { "x": -7, "y": -2, "chance": 7, "items": [ "flashlight" ], "ammo": 100 },
@@ -1437,15 +1421,7 @@
       { "x": -9, "y": -1, "chance": 7, "items": [ "rucksack" ] },
       { "x": -8, "y": -1, "chance": 5, "items": [ "m9" ] },
       { "x": -7, "y": -2, "chance": 5, "items": [ "223" ] },
-      {
-        "x": -7,
-        "y": -2,
-        "chance": 5,
-        "magazine": 90,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -7, "y": -2, "chance": 5, "magazine": 90, "ammo": 70, "group": "modular_m4a1" },
       { "x": -7, "y": -2, "chance": 7, "items": [ "EMPbomb" ] },
       { "x": -7, "y": -2, "chance": 15, "items": [ "mask_gas" ] },
       { "x": -7, "y": -2, "chance": 7, "items": [ "flashlight" ], "ammo": 100 },
@@ -1562,15 +1538,7 @@
       { "x": -6, "y": 1, "chance": 7, "ammo": 70, "items": [ "stanag30" ] },
       { "x": -6, "y": 1, "chance": 10, "items": [ "helmet_army" ] },
       { "x": -6, "y": 1, "chance": 15, "items": [ "gasfilter_med" ] },
-      {
-        "x": -6,
-        "y": 1,
-        "chance": 100,
-        "magazine": 70,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -6, "y": 1, "chance": 100, "magazine": 70, "ammo": 70, "group": "modular_m4a1" },
       { "x": -5, "y": 0, "chance": 3, "items": [ "cig_butt" ] },
       { "x": -5, "y": 0, "chance": 5, "items": [ "cig" ] },
       { "x": -5, "y": 2, "chance": 7, "ammo": 70, "items": [ "stanag30" ] },
@@ -1681,15 +1649,7 @@
       { "x": -6, "y": 1, "chance": 7, "ammo": 70, "items": [ "stanag30" ] },
       { "x": -6, "y": 1, "chance": 10, "items": [ "helmet_army" ] },
       { "x": -6, "y": 1, "chance": 15, "items": [ "gasfilter_med" ] },
-      {
-        "x": -6,
-        "y": 1,
-        "chance": 3,
-        "magazine": 70,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -6, "y": 1, "chance": 3, "magazine": 70, "ammo": 70, "group": "modular_m4a1" },
       { "x": -5, "y": 0, "chance": 20, "item_groups": [ "remains_soldier" ] },
       { "x": -5, "y": 0, "chance": 3, "items": [ "cig_butt" ] },
       { "x": -5, "y": 0, "chance": 5, "items": [ "cig" ] },
@@ -1798,15 +1758,7 @@
       { "x": -6, "y": 1, "chance": 7, "ammo": 70, "items": [ "stanag30" ] },
       { "x": -6, "y": 1, "chance": 10, "items": [ "helmet_army" ] },
       { "x": -6, "y": 1, "chance": 15, "items": [ "gasfilter_med" ] },
-      {
-        "x": -6,
-        "y": 1,
-        "chance": 3,
-        "magazine": 70,
-        "ammo": 70,
-        "items": "modular_m4_carbine",
-        "variant": "modular_m4a1"
-      },
+      { "x": -6, "y": 1, "chance": 3, "magazine": 70, "ammo": 70, "group": "modular_m4a1" },
       { "x": -5, "y": 0, "chance": 20, "item_groups": [ "remains_soldier" ] },
       { "x": -5, "y": 0, "chance": 3, "items": [ "cig_butt" ] },
       { "x": -5, "y": 0, "chance": 5, "items": [ "cig" ] },
diff --git a/data/mods/Military_Professions/npc/NC_ARMY.json b/data/mods/Military_Professions/npc/NC_ARMY.json
index 0c24f87ea7e5a..7eb640cf0662b 100644
--- a/data/mods/Military_Professions/npc/NC_ARMY.json
+++ b/data/mods/Military_Professions/npc/NC_ARMY.json
@@ -161,11 +161,7 @@
     "type": "item_group",
     "id": "NC_ARMY_rifle",
     "subtype": "distribution",
-    "entries": [
-      { "item": "modular_m4_carbine", "variant": "modular_m4a1", "prob": 50 },
-      { "item": "m14ebr", "prob": 35 },
-      { "item": "m249", "prob": 20 }
-    ]
+    "entries": [ { "group": "modular_m4a1", "prob": 50 }, { "item": "m14ebr", "prob": 35 }, { "item": "m249", "prob": 20 } ]
   },
   {
     "type": "item_group",
diff --git a/data/mods/Military_Professions/npc/NC_OPS.json b/data/mods/Military_Professions/npc/NC_OPS.json
index 508f043bd6247..363076a994c93 100644
--- a/data/mods/Military_Professions/npc/NC_OPS.json
+++ b/data/mods/Military_Professions/npc/NC_OPS.json
@@ -135,7 +135,13 @@
   {
     "type": "item_group",
     "id": "NC_OPS_rifle",
-    "items": [ [ "modular_m4_carbine", 50 ], [ "m14ebr", 35 ], [ "m249", 20 ], [ "modular_m27_assault_rifle", 50 ], [ "M24", 35 ] ]
+    "items": [
+      { "group": "modular_m4a1", "prob": 50 },
+      [ "m14ebr", 35 ],
+      [ "m249", 20 ],
+      [ "modular_m27_assault_rifle", 50 ],
+      [ "M24", 35 ]
+    ]
   },
   {
     "type": "item_group",
diff --git a/data/mods/Military_Professions/prof/army.json b/data/mods/Military_Professions/prof/army.json
index 35afa7711506d..c9a9e8c8acfed 100644
--- a/data/mods/Military_Professions/prof/army.json
+++ b/data/mods/Military_Professions/prof/army.json
@@ -23,8 +23,7 @@
           { "item": "gloves_tactical" },
           { "item": "ballistic_vest_esapi" },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "acog_scope", "grip" ]
@@ -138,8 +137,7 @@
           { "item": "gloves_tactical" },
           { "item": "ballistic_vest_esapi" },
           {
-            "item": "modular_m4_carbine",
-            "variant": "modular_m4a1",
+            "group": "modular_m4a1",
             "ammo-item": "556",
             "charges": 30,
             "contents-item": [ "shoulder_strap", "holo_sight", "m203" ]
diff --git a/data/mods/TEST_DATA/itemgroups.json b/data/mods/TEST_DATA/itemgroups.json
index 11d66399258e3..f76c291205b5c 100644
--- a/data/mods/TEST_DATA/itemgroups.json
+++ b/data/mods/TEST_DATA/itemgroups.json
@@ -76,14 +76,6 @@
     "type": "item_group",
     "id": "test_NPC_guns",
     "subtype": "distribution",
-    "entries": [
-      {
-        "item": "modular_m4_carbine",
-        "variant": "modular_m4a1",
-        "prob": 100,
-        "charges": 30,
-        "contents-group": "issued_carbine_mods"
-      }
-    ]
+    "entries": [ { "group": "modular_m4a1", "prob": 100, "charges": 30, "contents-group": "issued_carbine_mods" } ]
   }
 ]
diff --git a/data/mods/TEST_DATA/mapgen-test.json b/data/mods/TEST_DATA/mapgen-test.json
index 71bd1d0db5ff1..5aed57b5ea6cd 100644
--- a/data/mods/TEST_DATA/mapgen-test.json
+++ b/data/mods/TEST_DATA/mapgen-test.json
@@ -190,16 +190,7 @@
       "sealed_item": { "p": { "items": { "item": "farming_seeds", "chance": 100 }, "furniture": "f_plant_harvest" } },
       "place_loot": [
         { "group": "cannedfood", "x": [ 13, 13 ], "y": [ 22, 23 ], "chance": 90 },
-        {
-          "item": "modular_m4_carbine",
-          "variant": "modular_m4a1",
-          "x": 12,
-          "y": [ 9, 11 ],
-          "magazine": 100,
-          "ammo": 100,
-          "chance": 75,
-          "repeat": 30
-        }
+        { "group": "modular_m4a1", "x": 12, "y": [ 9, 11 ], "magazine": 100, "ammo": 100, "chance": 75, "repeat": 30 }
       ],
       "npcs": { "T": { "class": "guard", "add_trait": "ASTHMA" } },
       "place_npcs": [ { "class": "arsonist", "x": 9, "y": 1 } ],