I need to build a master and then mold out a MK75 76mm Gun (found on
the Hamilton class US Coast Guard vessels and Perry class FFGs) for a
friend of mine. Has anyone found any good sources of accurate info or
schematics of navy weapons systems? I've looked on the net several
times over the years and found very little other than photos to use
(which are great for the detailing but not of much help getting the
overall size, shape and dimensions correct.

Any help will be appreciated?