Question about straight wall reloading 45LC and 357 mag

[Rapier]

Spend the money on a Taper Crimp or Profile Crimp die set. Seat as a separate stage, then taper or profile crimp only until the case mouth is straight.
High pressure rounds, Ruger Only, causes case length growth. Case length growth due to pressure is very uneven. But the roll crimp die setting on your press, is in effec head-spacing off the case mouth! Bulging the case only on the over length cases, per your die setting, not the book trim to or the gun's chamber.

[pdgoutdoors]

As others have said, a case to long will cause inconsistent crimping. Make sure the cases are at least in between trim to length and max case oal (typically .010 difference between the two). Then make sure you are not overcrimping causing a bulge.

[Green Frog]

For my straight side revolver cartridges I like to finish up by passing each round through a Lee factory crimp die. As my last step I drop each round into a cartridge checker. I use ones from Dillon, Midway, and Lyman… all work equally well. When I follow this procedure I never have a problem with sticky rounds. When I don’t because I’m in a hurry, well sometimes things don’t go as well.
Froggie

[IroquoisEd]

I had this problem with the.45 colt. I bought the Lee factory crimp die which resizes and crimps at the same time. I liked it so much that I bought one for the.44mag.and the .357 . I also bought a Lee 4 holer turret press so I can leave the die block set up with all 4 dies. The only drawback is the 4th step when you reload, but it's worth it to me to avoid the trouble.
The only other problem that I know can cause similar trouble is lead fouling in the cylinder... I have a very nice K22 that I used shorts in, and the long rifle rounds stick going in and coming out... Someone suggested that I get the lewis lead remover. (IDK if I spelled that right) .

[Larry Gibson]

Take the boolits before you load them, see if they will fit through the cylinder throats by hand, from the front. If the boolits won't fit through the throats, which is a VERY common thing to happen, and after loading the ammo, your COA is long enough to allow the boolit to enter the throat, it will be met with interference and won't want to chamber fully.

If they WILL fit through the throats with finger pressure, you can eliminate interference with the throats being the problem

As Doug mentions, over sized bullets which do not slip fit into the cylinder throats is the usual cause of your problem.