hansol---you can ALSO buy the big brenneke slugs. The Brenneke SL-123BMM, 12 Gauge, 3 in, 1 3/8 oz, Black Magic Slug scoots at 1500+ fps!! For Rifled and Smoothbore Barrels. If you can get the 1 and 3/8 OZ Brenneke to speed along at 1500 fps you can get a round ball to 1600 fps.

I used the "Ballistic Products" Slug manual to develop some loads that were above 1500 fps and I'm sure you can to! Unfortunately I do not have that manual on me now but you can call Ballistic Products and ask them what load will get over 1500 fps using THEIR .715 round balls, and of course when you buy 25 of their .715 round balls I would assume they would provide you with the recipefor free... or of course you can always just buy their Slug Loading Manual and get that info there too. There are alot of slugs loads out there with speeds up above 1500 fps. And they don't kick that bad at all using modern powders.

However I'm with Daryl on this one. A WW round ball in .715 - .725 diameter would be confident medicine aganist a grizzly at 20 yards with muzzle velocity above 1200 fps. Sure 1500 to 1600 would make the INSURANCE company feel better but that was what I though the second barrel was for? (hahahahaaa!)