THE COEHORN MORTAR

On Sunday, December 11, 2005, my wife and I and our friend Ron took the Coehorn Mortar out to Rattlesnake Gulch for to shoot it for the first time. What a hoot that was!

I have owned the mortar tube for several years. I purchased it through Dixie Gunworks but never got around to building a base for it so it has sat unused in my Father-in-law's garage. Our Cowboy Action Shooting club has applied with SASS to host the Washington State Black Powder Championship next April. As a result I decided to get the mortar out and build a base for it so we could use it as a signal gun to get the event underway each morning.

Ron, who has a rather remarkable home shop with every tool imaginable, helped with fabrication of the iron parts and after a couple of weeks of work we had the base complete. For projectiles I had approximately 8 "Clamato Juice" cans which were the correct diameter to fit the 2 1/4 inch bore with just the right amount of windage. These I had filled with concrete while doing some cement work around the house a while back. They weigh exactly one pound each.

For a charge I decided to work up from a very light charge of 1/4 ounce of Fg black powder so I put together charge increments of 1/4, 1/2, 3/4, 1 and 1 1/4 ounces wrapped in tin foil. We also took the powder can with us to try loose powder charges.

The first charge (1/4 ounce) fired the one pound projectile approximately 180 yards! Wow! Big Boom...Lots of smoke...This thing is fun!

We proceeded to work up to the 1 1/4 ounce charge and it went over 400 yards. We tried loose powder and it worked fine. We also tried Pyrodex CTG (Fg equivalent) black powder substitute but this stuff had very little energy and barely fired the shell 75 yards.

Unfortunately when I went hunting for more "Clamato Juice" cans I found they no longer use the odd ball size can but rather have gone to a standard juice can size which is too small for the bore. This is a shame because the original cans were the perfect size and weight. Ron and I serched for a substitute and found that pool balls are just about the right size, being only a tad smaller in diameter than I would like. We purchassed a half a dozen used balls and will try them out at the first opportunity. They are only 5 to 6 ounces in weight and thus a bit on the light side but on the other hand this means they will require a smaller charge for any given range. As difficult as it is to find Fg or Cannon grade, or any black powder for that matter, reduced charge requirements are a good thing.

It may be several weeks before we get out to shoot it again but in the mean time I am building some of the necessary acutraments that go along with shooting artillery. I have made a linstock, vent pick, brush and gimlet, a spoon for cleaning out the chamber, a bore wiper and a crooked rammer. I still need to make a worm and a sponge. I will also build a "limber chest" to carry powder charges etc.

The next project is a cannon. Our friend Dotty has a cannon barrel in need of a carriage. The cannon barrel is 33 1/2 inches long with a bore of 2 1/4 inches (the same as the Coehorn Mortar). Ron and I will start in on the cannon carriage and hope to have it complete in time for the match in April also. The next blog on this topic will include some pictures.