The Legionnaires of Victory company and beyond are no stranger to grenades and the combat multiplier they provide. The compact delivery system hasn’t changed much in the thousands of years since they were produced, but were adapted to modern military tech by the time SGT Chhun threw them into windows on Kublar.
At its core, a frag grenade is a metal body packed with explosives and set with an activator or fuse. The grenades of today are pretty simple by Repub standards. Pull the safety retaining pin, which will allow the arming lever (the spoon) to detach when thrown, and fling it where you intend to bring it. The three second fuse will count down and detonate the boom, which puts pressure on the metal casing, causing it to blow outward into shards of metallic flack. The concussion and fragmentation leads to a killing radius of 5 meters with a wounding radius of 15.
Newer, more modern grenades are even fitted with an impact actuator and longer burn times for the fuse until it goes off.
Far into the future on Kublar, we see then Sergeant Chhun toss a fragger into a window to deal with hostile insurgents looking to do Victory Company dirty. While the nature of the grenade he uses is the same as they are today, the design has taken significant leaps into how the munition performs.
Tossing the grenade remains the same. But once the actuator times out, we see the Repub has seen fit to up its lethality game. The first stage of the grenade goes off, detonating the casing into 2 mm pieces of flak which shreds flesh and weakens modern body armor. This releases four micro balls packed with more explosive which then detonates. The shrapnel from the secondary blast releases fine, needle-like shrapnel in all directions, finding the special nooks and crannies in armor to cut through.
Chhun comments in his memoir that the first boom knocks you down and breaks your stuff, but the second always finds an artery.
For more on the fragger and feeling the whoomp-whoomp of them going off, check out Legionnaire!
When the pin is pulled Mr. Grenade is everyone's friend...well no, not really. Excellent info drop!