I have a 26 pound 4 ounce cornish x (Big Boy). He is 14 weeks old yesterday. He crows and mounts turkeys that are laying down to rest. When they stand up he usually falls off and starts to run like crazy because he knows that turkey is going to chase him around the 1/2 acre pen at least once. He always out runs them because he is able to run through the flock of turkeys to lose the purser (maybe the purser looses interest--who knows).
Last year we kept 25 cornish x (cockerels) to see how big they would get; average dressed weight was 17 pound 2 ounces; the largest being 20 pounds 7 ounces. So, 33 pounds live weight is not out the question if adequate exercise and nutrition were given during their whole life.
The official record is 23 pounds 3 ounces--the weight was verified by a veterinary clinic scale years ago (probably no more accurate than most digital ones currently available). Cant remember the gentlemans name but he lived in Australia, the breed was a White Sully (developed in California), which is close to the modern cornish x. It was about 20 or so years ago.
Good luck!!