Rick not sure. But this thing could shoot a 550 pound shell at almost 3700 fps. That's like a 7'mm weatherby.... It's the same type used at Anzio. More amazing is the stuff Krupp was showing up at world fairs in the late 1800s. When the rest of the world were still fixated on cast iron muzzle loaders these guys were making steel breechloaders that fired half ton shells. Google Krupp 1867 cannon and check the images. Skoda out of Austria was a close second or first depending on who you ask. I am an old artillery buff....