At the Siege of Cwl Gen, Jarrun Iremonger bough time for the Free Dwarf armies to march south and regroup with their kin by emptying his workshop and the hold’s entire armory.
Well over a hundred warmachines held the walls of the hold. For seven days and seven nights they fired continuously, making the Abyssal Dwarfs pay for every step conquered.
The siege only ended when the last of the Free Dwarfs managed to escape through tunnels when the last of the ammunition had been all but depleted. The last of the garrison bought themselves time by detonating the last of their powder reserves, bringing the hold itself down upon the advancing slave hordes.