Aside from the weapons produced by regular factories, the rebels also acquired 15 special cannons known as "Flying Thunder" through special channels. These strange-looking cannons, shaped like water barrels that fired explosive packets, received widespread praise once they were used. Although there were some issues with accuracy and range, the destructive power of the 10-kilogram disc-shaped explosive packets was several magnitudes greater than the solid shot and shrapnel fired by six-pounder cannons. When facing formidable strongholds, the insurgent army only needed to launch a few explosive packets to ensure that there were basically no survivors left inside the fortifications. As these game-changing siege weapons rapidly eliminated peripheral strongholds, the pressure on the defending troops continued to mount. Around 11 p.m., with the last few strongholds blown into the air, the Avo Headquarters Building also fell.