30-30 is absolutely fine for whitetails. When I was growing up in northern Wisconsin, most of us hunted with guns in that class. 30-30 was the most common. I had a slide-action .30 Remington (still do, but finding ammo for it is a pain), which was Remington's now nearly extinct answer to the 30-30. Several friends used .32 Specials. They all killed deer just fine.