This is our favorite lower receiver.  It's not the cheapest mil-spec lower on the market, but Smith & Wesson's quality is second to none.

Firearms must be shipped to a Licensed Federal Firearms Dealer (FFL) in your state of residence and Advanced Tactical Solutions must have a signed, legible copy of the receiving dealer's license prior to shipment. Please verify your local and state laws and make prior arrangements with your dealer prior to purchase. Your dealer can fax their FFL to us at (866) 677-5579.