I'll do the four noes with a warning. There are some very bad lead bullets sold commercially. The most common problem is that they are undersized. Lead bullets absolutely have to be bigger than groove diameter. There is also a fad for overly hard bullets. If the label says Magnum or Hard Cast, leave it there unless you are planning full magnum loads. Third is lube. Shiny, hard, bright colored lubes are generally a mistake. The commercial casters are often more concerned with visual appeal, lube staying in place in shipping, and cheapness than they are in what works.
I warn you of this so that you won't be put off for life and cussing our advice if you do run into a bad batch. There are good brands out there and it is very little trouble to cast your own. This is one of the rare situations when homemade is almost certain to be as good as the best boughten.