A grenade is a short fuse and a bad day in a small package. The hand-tossed bombs have origins dating back centuries, with more modern types first seeing use in World War I.

From eco-friendly hand grenades to next-generation aircraft for special forces, defense vendors from around the world brought their best to catch the eye of the U.S. Army this week.

The scalable hand grenade the Corps is looking at is manufactured by Nammo — the makers of the Corps’ single-shot light anti-tank rocket launcher known as the M72 LAW.

Members of the 278th Armored Cavalry Regiment of the Tennessee Army National Guard on Wednesday became the first conventional soldiers to detonate an M67 fragmentation grenade from a drone-borne ...