This is an complete set of parts to assemble a .40 S&W upper with a 7.5 inch barrel. The set comes complete with a Quarter Circle 10 .40 S&W bolt and barrel.
Aero Precision M4E1 enhanced upper.
Aero Precision AR15 7 inch, Enhanced M-LOK Handguard, Gen 2 (1.72" inside diameter fits most muzzle devices and 1.5" suppressors)
Quarter Circle 10 7.5 inch .40 S&W barrel with .578-28 Threading
Quarter Circle 10 .40 caliber bolt.