Home / Parts / Buffer Tubes and Kits / Toxic Mil-Spec Steel castle nut “Toxic Arms Mil-Spec Carbine Stock Hardware Kit” has been added to your cart. View cartContinue shopping Toxic Mil-Spec Steel castle nut$395 Toxic Mil-Spec Steel castle nut quantity Add to cart Category: Buffer Tubes and Kits Product ID: 2405 Description Description Mil-spec carbine castle nut/lock ring for securing lock plate on an adjustable stock for AR-15, M4 Related products Toxic Mil-Spec Steel end plate $399 Toxic Mil-Spec buffer tube (6 Position) $1795 Sale! Toxic Arms Mil-Spec Carbine Stock Hardware Kit $5999 Original price was: $5999.$2995Current price is: $2995. Out of stock Sale! Timber Creek GM Quick Disconnect END PLATE $2499 Original price was: $2499.$1899Current price is: $1899.