I do not know who makes them. I do know that they are made by a large machine shop in the US who suppies them to factories and large retailers. the guy I buy them from is a small manufacturer who builds custom ar-15s and he uses them in the guns he sells for 1500.00. He wants to protect his source and keep me from buying the direct. they are a good looking bolt and for 139 shipped you cant beat the price.Manufacturer?