Upper Receivers guides.
Explainers covering stripped uppers, assembled uppers, receiver materials, fitment, and compatibility.
Upper ReceiversWhat Is a Side Charging AR-15 Upper
Learn how side charging AR-15 uppers differ from standard rear-charging uppers and what buyers should compare before choosing one.
Upper ReceiversWhat Is an AR-15 Upper Receiver?
Learn what an AR-15 upper receiver includes, how it connects to the lower, and which parts matter when planning an upper build.
Parts resource
Ready to compare AR-15 parts?
Use the guide above to narrow your parts list, then browse AR15Parts.com for upper receivers, barrels, handguards, BCGs, charging handles, and build components.