the .357 case specs .379" from the mouth all the way down to the groove above the rim. Sizer dies normally deliver something smaller than that, as far down as they reach.
If your dies aren't doing that, then there is an issue with the dies. If they are, then the dies aren't at fault and something else is causing your problem.
Dirty chambers? soft brass? over expanded case heads from too hot loads are just some of the things that can cause the "last 1/2" or 1/4" to be "sticky".
I've used Lyman dies since the 70s and my .357 set is from that era and still makes fine ammo.
I've never used Starline .357 so i can't speak to it, but I have used some Starline stuff in other calibers without issues.
Maybe your dies are worn out, no way to tell over the internet. What are the dimensions of your sized brass?