Union battery with 13-inch (330 mm) seacoast mortars during the siege of Yorktown, Virginia. (1862)

https://en.m.wikipedia.org/wiki/Siege_of_Yorktown_(1862)

On the morning of April 17 it became obvious that no assault could be attempted at any point. At this point McClellan acquiesced to conducting "regular approaches" and ordered parallels to be dug for heavy artillery. The siege preparations at Yorktown consisted of 15 batteries with more than 70 heavy guns, including two 200-pounder Parrotts and twelve 100-pounder Parrots, with the rest of the rifled pieces divided between 20-pounder and 30-pounder Parrotts and 4.5-inch (110 mm) Rodman siege rifles. These were augmented by 41 mortars, ranging in size from 8 inches (200 mm) to 13-inch (330 mm) seacoast mortars, which weighed over 10 tons and fired shells weighing 220 pounds. When fired in unison, these batteries would deliver over 7,000 pounds of ordnance onto the enemy positions with each volley.