I used to deal with Joe Gibbs racing. Try to call them and see who they have do their DLC engine lifters. Seems like it would be very expensive to accomplish very little. You need to find out if the DLC thickness would interfere with function of the bolt. DLC is for wear resistance under sliding contact and extreme pressure. I never heard of an action wearing out. I was only concerned with disbond of the coating. with different processes. I did the work 10 years ago. Not familiar with how it's done. Is it a problem coating internal sufaces?looking for reliable DLC coater for a Kart barrel for my 1911 and maybe slide. Who is good?