My Sauer hammer drilling is 16X16X11.15X65. The rifle cartridge is a big long .44 caliber variation that is pretty common but hard to find cases for. I have a bag of cases, so I am set for life. It will put a big hole in anything you shoot with it. The top lever selects the rifle barrel and a side lever opens the gun. The rifle barrel is a perfect fit for a 2 1/2" .410, which is exactly 65MM, same as the rifle cartridge. The gun handles the .410s very nicely and doesn't lead up badly at all. I recently let a friend strip, refinish, and point up the checkering. This resulted in a very fancy piece of Juglans Regia, not characteristic of an early Sauer. The Krupp steel gun was made around 1905. A friend sold me this little gem for $200 because he had no practical use for it.