Thank you. So I am doing math in public here.

Center of the trunnion to the ground for Type 1 field carriage is 44.5 inches and the trunnion diameter is 3.67 inches.

The trunnion diameter is 4.2 inches for 12 lbs Napoleon and 24 lbs field howitzer resulting in a Type 2 field carriage. That makes a trunnion diameter difference of .53 inches. Is it safe to assume that the trunnion center for a Type 2 is the difference between the trunnion diameter (.53 inches) divided in half (equals .265 inches) and added to the Type 1 field carriage center of trunnion (44.5 inches) equals 44.765?

Why I am doing this is that I am making a "tool" for my field study work to determine weapon line of sight, depression, and elevation. I do not believe that .265 inches will make a difference for Civil War field artillery. It would make a difference on a M1A1 Abrams tank at 1,500 meters but I think I am safe with Civil War weaponry.

Please let me know if you have any questions.

Respectfully,

Gerald D. Hodge, Jr.
M.A. Military History - Civil War Concentration
Research - Preservation
Historian: 39th Georgia Volunteer Infantry Regiment