Awhile back, Steve of The Firearm Blog posted "Smallest black powder artillery ever made". That post has images and video of miniature mortars, cannons and gonnes. After seeing that, I knew I had to get into the miniature arms race. For my first effort I used the provided plans.
Here is the Nano-Mortar:
Remington Airguns “War on Squirrels”
13 minutes ago