OK, plenty of info here, the full range by the look of it. Some of the 'guaranteed' 50 and 100 yd groups sound too good to be true! Also, looks like they still make a felt-based slug for the traditionalists!

Brenneke Webpage

Note that the slugs range up to 1 3/8-oz 12-bore 3-inch magnum with over 3000 ftlbs at the muzzle! Ouch!

Also managed to find the Brenneke sabot, called "KO", but they are not likely to take anything away from the originals.