I have a Fox Sterlingworth that had the barrels hot blued about 2 years ago.It has had a fair amount of use since then.That is not to say I they won't have problems later down the line.The guy who blued them said he has never had any problems with hot blueing doubles, something about removing them from the hot bath and not leaving them in to long I don't know all I know is they turned out great with no problems yet.