It's funny, a lot of people say that a .357 round out of a revolver is a marginal deer gun. Not because it really is, but because most people don't make a good shot with the revolver.
Instead of blaming the person, who with any handgun caliber would be only a decent shot, they blame a caliber that leaves less room for error in a short gun. Let's face it, some calibers do make up for poor markmanship. Right or wrong, that's a fact of liife.
That's why a lot of the guys my family used to hunt with made fun of Dad who used a .44 mag rifle as his secondary hunting gun for decades. That rifle took a lot of deer when most said it would be worthless.
What made it lethal for my father, and then to a lesser extent with me? Accuracy. Ok, so until I got my buck fever under control, I did wound two deer and clean missed another. After that I took two deer with that .44 that were one shot one kills before I stopped hunting for a while due to situations in my life (school and work mostly).
If you can put the bullet where it needs to go, a rifle chambered in .357 mag will work very well.
PS - My take on the 30-30 is simple. It's a round that has taken a lot of lives for a long period of time. If I had a rifle chambered in it, it would be used as my backup gun. However, seeing as I don't own one in that caliber, I will not buy one. It is a round that has a lot of meaning for my Father due to his experiences hunting as a youth. Much like why we both enjoyed using the old Ruger chambered in .44 to hunt with. We love the round, yet no longer hunt with it.