Powder keg

Powder kegs are amongst the most powerful explosives in Britannia. The Avatar frequently used their destructive power to blow down doors and remove other obstacles from his way. Whenever the Avatar encountered a door that could not be unlocked, it was frequently the destructive force of powder kegs that opened the way.

According to Vetron's Guide to Weapons and Armour, powder kegs have an effectiveness rating of "16" (other sources have rated this as high as 40, however).

Trivia

 * A powder keg is the most likely way of liberating the Hoe of Destruction from Mack's shed in Ultima VII.