Mil STD 1595 is an DOD aerospace fusion welding standard... It has been superseeded by AWS D17.1
Mil STD 2219 is also an aerospace fusion welding specification. While 2219 is still in effect it is important to note that Department of Defense Aerospace and Missle Code Mil-Std 2219 requires its welders to comply with D17.1 for welder performance qualification.
Pressed for time now... if you have more specific questions keep asking.