Re: Contender issue...........
If it's an original Contender, there is a little butterfly looking piece in the action that can cause problems (sorry, it's been so long I've forgotten the nomenclature).
Also, if your rounds are a little too long or the shoulder isn't set back enough you'll have the same problem. Never seen it happen with .30/30, but certain cases will thicken in the neck and cause difficult chambering.