Jack Melton pass on to me this interesting email thread and suggested I post it on the web site which I did. I thought I'd put the link here as well:
http://www.bulletandshell.com/Dahlgren_Gun/Hartford_Dahlgren.htmas our members might be interested in this. I recommend reading it from the bottom up as it's an email thread and will flow better that way. If you are into cannons it might be worth a trip to Petosky, Michigan to see all the big guns.