Source: Dungeon Masters Guide

Explosives

A campaign might include explosives from the Renaissance or the modern world (the latter are priceless), as presented in the Explosives table.

Explosives

Renaissance Item Cost Weight
Bomb 150gp 1lb.
Gunpowder, keg 250gp 20lb.
Gunpowder, powder horn 35gp 2lb.
Modern Item Cost Weight
Dynamite (stick) - 1lb.
Grenade, fragmentation - 1lb.
Grenade, smoke - 2lb.
Grenade Launcher - 7lb.

Bomb

As an action, a character can light this bomb and throw it at a point up to 60 feet away. Each creature within 5 feet of that point must succeed on a DC 12 Dexterity saving throw or take 3d6 fire damage.

Gunpowder

Gunpowder is chiefly used to propel a bullet out of the barrel of a pistol or rifle, or it is formed into a bomb. Gunpowder is sold in small wooden kegs and in water-resistant powder horns.

Setting fire to a container full of gunpowder can cause it to explode, dealing fire damage to creatures within 10 feet of it (3d6 for a powder horn, 7d6 for a keg). A successful DC 12 Dexterity saving throw halves the damage. Setting fire to an ounce of gunpowder causes it to flare for 1 round, shedding bright light in a 30-foot radius and dim light for an additional 30 feet.

Dynamite

As an action, a creature can light a stick of dynamite and throw it at a point up to 60 feet away. Each creature within 5 feet of that point must make a DC 12 Dexterity saving throw, taking 3d6 bludgeoning damage on a failed save, or half as much damage on a successful one.

A character can bind sticks of dynamite together so they explode at the same time. Each additional stick increases the damage by 1d6 (to a maximum of 10d6) and the burst radius by 5 feet (to a maximum of 20 feet).

Dynamite can be rigged with a longer fuse to explode after a set amount of time, usually 1 to 6 rounds. Roll initiative for the dynamite. After the set number of rounds goes by, the dynamite explodes on that initiative.

Grenades

As an action, a character can throw a grenade at a point up to 60 feet away. With a grenade launcher , the character can propel the grenade up to 120 feet away.

Each creature within 20 feet of an exploding fragmentation grenade must make a DC 15 Dexterity saving throw, taking 5d6 piercing damage on a failed save, or half as much damage on a successful one.

One round after a smoke grenade lands, it emits a cloud of smoke that creates a heavily obscured area in a 20-foot radius. A moderate wind (at least 10 miles per hour) disperses the smoke in 4 rounds; a strong wind (20 or more miles per hour) disperses it in 1 round.