For Fall â€™62 release: 76 high rated Â½ hours for syndication! The eminently successful REBEL enjoyed top Sunday night audiences on ABCâ€™s Television Network for 2 solid years. A 32.9% average share-of-audience* put THE REBEL into 9,729,000 homes each week during the 1960-â€™61 season. Already bought and programmed by the NBC Network** THE REBEL faces no hiatus this summer. This invaluable exposure of your property will cover 12 weeks this summer on the network: A springboard for your local programming this fall. So rally â€˜round THE REBEL, boys. Write for full details today; or callâ€¦ *National Nielsen, Jan.-May, 1961 **Wed. 8:30-9PM starting June 27 (Replacing Joey Bishop) 
In my article about The Rebel I note that the series was cancelled not due to low ratings (as the advertisement indicated, the series was doing quite well) but because ABC was moving away from action/adventure shows. There may have been a little more to it than that. Apparently there were plans to expand The Rebel to an hour before it was decided to end the series. I’ll do some more research and update my article in the next few days.
1 Advertisement in Television Magazine, June 1962, Page 45.