Yogi:
I recently surfed the Rottweil/ Brenneke web-pages for another thread, and found the ballistics for the "Original Brenneke 12-bore 3-inch Magnum" (half-way down this page) to be astounding!

How does a 1 3/8 ounce slug at 1500 fps for 3000 ftlbs ME sound?!

BIG BORE knockdown power indeed!

Forget about those piddly round balls, mate.