What are the differences between a "Type I and Type II" issue cap?

The typology of the forage caps seemed to stem from the Kloster and Howell book published by the Smithsonian. It basically divided the caps into two “styles”, based on the measurement of the top disk and shape of the visor.        
Type I issue cap

Type I forage cap

Smaller disk (around 5 ¼”) with a curved “duckbill” visor. Considered by some as being an "early war" cap, it is in truth seen in pictures throughout the entire war. John P. Langellier's book Army Blue, lists this cap as the model 1858.

Larger disk (5 ¾") with a flat squred visor). Considered by some as being an "late war" cap, it is in truth seen in pictures throughout the entire war. John P. Langellier's book Army Blue, lists this cap as the model 1861.


 

As an aside, these are the steps involved in stamping and forming our chinstrap buckles.Basically it is a 5 step process, which are, from left to right, blanking, punching first hole, then second, and finally forming.