We had approximately 120,000 pieces of these custom shoulder bolts manufactured domestically in the USA for our gun manufacturing customer. The shoulder measured .185 X 1/2 and 8-32 thread was rolled. To save on cost we incorporated a convex relief underneath the head in leu of a machined relief, allowing us to complete the entire head portion with cold heading. The shoulder was centerless ground to a +/-.001 diameter tolerance and we also made sure to meet the .127/.125 across flats requirement on the 1/8 hex socket drive, which was a critical feature for optimal key engagement. Full certs were provided with the parts.