Complete Upper Assemblies
A complete upper is a full AR-15 upper half that includes the upper receiver, a barrel, a muzzle device, and (optional) bolt carrier group.
What is the advantage of buying a complete upper?
Because it is the complete upper half of the rifle, all you need is a lower half and you will have a fully functioning rifle. Many people buy complete uppers in .22LR or .300 Blackout, and this allows you to quickly swap to different calibers by just switching upper receivers.
