diff --git a/go-services/inventory-go/ingest.go b/go-services/inventory-go/ingest.go
index 04ab99e3..213c60cc 100644
--- a/go-services/inventory-go/ingest.go
+++ b/go-services/inventory-go/ingest.go
@@ -245,6 +245,49 @@ func (s *Server) handleDeleteItem(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, map[string]any{"status": "deleted", "item_id": itemID})
 }
 
+// POST /admin/backfill-od — recompute od_rating for all weapon rows from stored
+// raw JSON. Internal-only (service is bound to loopback/compose). Idempotent.
+func (s *Server) handleBackfillOD(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	rows, err := s.pool.Query(ctx,
+		`SELECT rd.item_id, rd.original_json FROM item_raw_data rd
+		 JOIN items i ON i.id = rd.item_id
+		 WHERE i.object_class IN (1,9,31)`)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]any{"error": err.Error()})
+		return
+	}
+	type upd struct {
+		id int
+		od float64
+	}
+	var updates []upd
+	scanned := 0
+	for rows.Next() {
+		var id int
+		var oj map[string]any
+		if err := rows.Scan(&id, &oj); err != nil {
+			rows.Close()
+			writeJSON(w, http.StatusInternalServerError, map[string]any{"error": err.Error()})
+			return
+		}
+		scanned++
+		if od, ok := computeOD(oj); ok {
+			updates = append(updates, upd{id, od})
+		}
+	}
+	rows.Close()
+	updated := 0
+	for _, u := range updates {
+		if _, err := s.pool.Exec(ctx, "UPDATE items SET od_rating=$1 WHERE id=$2", u.od, u.id); err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]any{"error": err.Error(), "updated": updated})
+			return
+		}
+		updated++
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"scanned": scanned, "updated": updated})
+}
+
 func parseNaiveTime(s string) time.Time {
 	if s == "" {
 		return time.Now().UTC()
diff --git a/go-services/inventory-go/main.go b/go-services/inventory-go/main.go
index 51611dcc..47140c0a 100644
--- a/go-services/inventory-go/main.go
+++ b/go-services/inventory-go/main.go
@@ -100,6 +100,7 @@ func main() {
 	mux.HandleFunc("POST /process-inventory", srv.handleProcessInventory)
 	mux.HandleFunc("POST /inventory/{character_name}/item", srv.handleUpsertItem)
 	mux.HandleFunc("DELETE /inventory/{character_name}/item/{item_id}", srv.handleDeleteItem)
+	mux.HandleFunc("POST /admin/backfill-od", srv.handleBackfillOD)
 	// Suitbuilder (port of suitbuilder.py router, mounted at /suitbuilder).
 	mux.HandleFunc("POST /suitbuilder/search", srv.handleSuitSearch)
 	mux.HandleFunc("GET /suitbuilder/characters", srv.handleSuitCharacters)