The fight to get my big cat into his carrier eventually left me bleeding and defeated. So, I got a different kind of carrier.

My vet's office had a plastic version of the old style cardboard box carrier for under $10. This seems to work great. He still doesn't like the box, but I can get him into it without harm, and there is nothing to hurt him once he is inside. It has more room inside, and seems more like the cardboard boxes he loves to hide in at home. Good luck and don't give up!