There are several surviving caps of nearly identical pattern, materials, and construction that are presumed to have been a product of the Columbus Depot.  The cassimere cap body is uniquely made without a separate band, the brim is machine bound oilcloth, chinstrap buttons are a variety of non-military buttons, osnaburg is used as the lining, and the oilcloth sweatband is very crudely attached.  Along with the artillery version he is also making, Greg Starbuck will be making exact copies of the infantry version of this cap for We Soon Got Proud!  These work great for an Army of Tennessee artillery impression and can, of course, be used with your infantry impression as well.