Another hobby of mine is firing off my mortar cannons.  I have two of them that I made from solid round stock.  Bored them on a big milling machine.  I like to put a gallon jug of gasoline about 12 inches above the cannon and it makes a huge fireball. 

If you want to view the photos or videos just click on the links below.

My biggest cannon is 19 inches long with a 14 inch deep bore.  The bore diameter is 2-3/4 inches and the overall diameter of the cannon is 6-1/8 inches.  I shoot it straight into the air and use 1-1/8 cup of red dot smokeless shot gun powder.  I light it off electrically using a 12 volt 100 watt halogen bulb filament.  That way it is safely detonated.

This is a video of my smaller cannon.  The charge was one half cup of powder with a coffee can of gasoline positioned above the cannon.  We fired it at night

http://lchesak.home.insightbb.com/Small_cannon_video.MPG

Here is a video of the big cannon fired in a large corn field.

http://lchesak.home.insightbb.com/Big_Cannon_video.wmv

Here is a photo of the cannons

http://lchesak.home.insightbb.com/Photo_of_cannons.bmp

I have some other photos of the cannon that I will have to dig up.

 Here are a couple of photos of the small cannon exploding with gas.. pretty impressive

http://lchesak.home.insightbb.com/Cannon.jpg

http://lchesak.home.insightbb.com/Cannon2.jpg