Hello

Well weapon engineering is a specialisation under mechanical engineering as post graduation. There are many institutes abroad which have it. Courses categorized under Weapons Engineering PG in Air Armament Engineering PG in Combat Vehicles Engineering PG in Guidance and Navigation Control Engineering PG in Guided Missiles Engineering PG in Microwave and Radar Engineering Career possibilities in the field of weapons engineering Since weapons are not the business of common people and their research, development, maintenance and repair are highly regulated, you can find a job in weapons engineering in the military alone.
I hope it will help you
Good luck....

Hey Sirigade Janabai! Definitely yes weapon designing is a branch under mechanical engineering. Weapons engineering is that branch of study that deals with the research, development, production, repair and maintenance of weapons and other artillery associated with it. As a weapons engineer, you will have to deal with collection of equipments, structures, vehicles and communication systems which are specifically designed for warfare.