Luth-AR 16 Lightweight Barrel Complete Upper Receiver, 223 Remington, Black Finish, 15 Palm Handguard Keymod, 1:9 Twist, Complete Barrel Assembly w/BCG, Fits AR-15 BAA3-L16 The Luth-AR 16" Lightweight Complete Upper Barrel Assembly Starts with a 16"" 223 Remington Lightweight barrel made from 4140 Chrome Molly with a 1-9" twist mated to a A3 Flattop receiver which includes a bolt carrier" charging handle" forward assist and ejection port cover. The upper is then topped off with a lo-profile gas system and an ergonomic 15" Palm Handguard with KeyMod slots and a Picatinny top-rail.