http://www.african-hunter.com/Rifle_Choice_4_Dangerous_Game.htm
I don't know if this has been posted but it's about lions and leopards but I bet it's the same with tigers, shotguns are out, you need 2250fps to stun the cat or else you're hoping for organ damage and he'll be on top of you before he dies from that!
"A .303 with good bullets is still a better weapon for dealing with a wounded lion than any shotgun. As noted in my article on game toughness, a bullet needs to be travelling at over 2250fp to exploit a cat's susceptibility to shock. No shotgun load achieves this and you therefore have to rely on killing the animal by destroying organs. With a perforated heart a lion can still move for up to 8 seconds - at 15+ metres a second: perfect medicine in a close quarters confrontation. I wouldn't trust even a Breneke slug to get through the chest muscles on a charging lion at any but point blank range. Unmarked hunters are those who do not let anything nasty get anywhere near point blank range until after it has been skinned.