Assuming you have a lever-action 30-30?
If so, yes, you do have to FL size every case, every time it is fired.
Neck sizing will not work for ya.
Yes, you will have to trim every case, because you will have to crimp every round for use in a tubler magazine lever-action.
That requires all cases to be the same exact length, unless you buy a Lee Collet Crimp FCD crimp die.
But even then, out of every caliber I reload for, I have found more case length & neck thickness variation in different brands of 30-30 cases then any other caliber.
They simply must be trimmed to do a decent job reloading them.
rc