Greetings Gentlemen,
This is my first post ever here after lurking and reading for about a month. Like many of you perhaps, I was glad for the excuse to shake the neighborhood last night. I have a bronze cannon about 30 inches long, 13/4" bore on a naval carriage. It's a cast of an original 1702 spanish deck gun. Got in a few good blasts last night even though it was about 20 below zero (F) here in Fairbanks, Alaska. ... roll it out on the deck, BOOM...back in to swab and let it rest for a while before reloading...
But, all that is just by way of introduction. I have recently been taken by the obsession to build a bowling ball mortar. I managed to find my way here, and I am so glad to have found these forums! Tons of great information, especially the safety information, and the manufacturers 'reviews'...anyway, I managed (after MUCH labor) to find a cylinder and lopped off the end with a chop saw (many sparks). I was greatly relieved to slide my first ball down the bore and find that it fits!
I don't have much machining capicity on my own, but I have an 'associate' who is a cannon buff and I talked with him and he is ready and willing to help me with the next step. He owns an extensive machine shop, and I'm looking to get started this week.
Here's my first question: Is it necessary to attach a powder chamber, (per the Florida BBM design?) out of say a 5 inch bit of round stock with a 2" X 2.5" chamber bored in it, to the base of the cylinder? Or can one simply remove the valve (already done this) and thread in or weld on some sort of plug, thereby using the natural recess in the bottom of the cylinder for a powder chamber?
I like the blunt looking end without the 5" 'nipple' of the powder chamber attached for aesthetic reasons. But, if it IS necessary, then so be it. It seems like in surfing the web, I've found BBM's built both ways.
After I cross this hurdle, I plan on working on the trunion issue.
My second question is related to 'windage'. The first ball I tried had a nice loose 'rattle' in the bore. Perhaps 1/8" or slightly more space. Another ball, a new one, unbored for fingers, has even less, perhaps 1/32" or less even. That seems a bit tight to me? I'm going to err on the side of caution and I did read the article on windage here on the site, but I guess I'm looking for some field experience here. I plan on using pretty light loads, designed to drop the ball at around 100 yards mostly. What do the 'experts' say?
Thank you gentlemen for your help! I wish you all a happy year and good cannoning!
-Owen Guthrie
Fairbanks, Alaska