CMMG 55CA6C7 Receiver Extension Kit includes Carbine Style Buffer & Action Spring for for AR-15
https://www.tandktactical.com/shop/815835017389-cmmg-55ca6c7-receiver-extension-kit-includes-carbine-style-buffer-action-spring-for-for-ar-15-543
https://www.tandktactical.com/web/image/product.template/543/image_1920?unique=50449e4
This CMMG Receiver Extension kit comes with a carbine buffer assembly and a carbine action spring.
