We get these custom cold headed screws with black nitride finish manufactured 100% domestically for our gun manufacturing customer using 302 stainless steel material. 1/4-28 partial thread is rolled to .75″ in length and overall length is set to 1.695″. Black nitride finish was added at 980 to 1050 degrees and effective case thickness of .0005 to .0020″. Full certs were provided with the parts and we release through multiple shipments per an annual Blanket Purchase Agreement we have with our customer.