Rieco, many "Carbine" Length Quad Rails will fit such as : budsgunshop.com/catalog/product_info.php/products_id/714005311/UTG+PRO+4%2F15+CARB+QUAD+RAIL+BLK or budsgunshop.com/catalog/product_info.php/products_id/85810/Firefield+FF34001B+Quad+Rail+M4+Alumi