I have taken several bison and buffalo with Lead Bullet Technologies 430g cast solid at 2000fps (22" bbl). I have also taken 2 water buffalo with the 405g Kodiak Bullet by Alaska Bullet Works. They were going 2170 in a 20" bbl. You can get them commercially loaded from Grizzly Cartridge. I had better results with the Kodiak on closer shots (55yards or less) to the heart/lungs. I found if the cast bullet does not break the shoulder it will take a little longer for the animal to go down. The wounds and reaction were more dramatic with the Kodiak Bullets.