The family of 68pdr guns

On February 19, 1999, I put together a table of 68pdr guns for use in the my ship designs. This was a favorite ironclad shot weight:

Dia     Shot wt  Length  Wt of piece  length of piece projecting length MV

5.15in  68 lbs   25      2.28 tons    10ft-9in         6ft-5in          1,600 ft/sec
5.15in  68 lbs   30      2.73 tons    12ft-10in        7ft-9in          1,960 ft/sec
5.15in  68 lbs   35      3.19 tons    15ft             9ft              2,200 ft/sec
5.15in  68 lbs   40      3.64 tons    17ft-2in        10ft-4in          2,400 ft/sec
5.15in  68 lbs   45      4.1 tons     19ft-4in        11ft-7in          2,700 ft/sec
5.15in  68 lbs   50      4.55 tons    21ft-5in        12ft-10in         2,850 ft/sec