Expo Arms

Overview

The Expo Arms Mil-Spec Steel Castle Nut is a standard component designed to secure the buffer tube to the receiver, ensuring stability and proper function during operation. Made from steel with a phosphate finish, this castle nut provides reliable durability that builders can count on in their AR-15 configurations. This part is commonly found in builds featuring a mid-length gas system chambered in 5.56 NATO, making it a versatile choice for a variety of setups.