My dies for my 30/30 sometimes has the crimp fail and the bullet push back some
What brand of dies are you using??
Unless the dies are actually physically defective/damaged (which is unlikely) the usual problem is the OPERATOR, who adjusts the die settings, and everything else.
Uniformity of case length is important to making a uniform crimp. You don't have to trim after each firing, but you have to check before each loading, and trim IF NEEDED.
Adjusting for proper seating and crimping is not rocket science, but it is something that can be done incorrectly.
I've been loading .30-30 with the same Lyman dies that I got
used in the early 1970s. Never bothered with a Lee 'factory crimp die". Never needed one, don't need one now.
Sounds to me like you simply need to SLIGHTLY increase the amount of crimp (assuming that you are doing it correctly now). 1/10th or 1/8th more turn on the seater die body (and corresponding change to the seater plug), load some test rounds and see if the problem persists.