Check out Steve Regwell's web site, 303britsh.com. He has an article I wrote a few years ago about using cast bullets in Lee Enfields. There is a lot of information learned "the hard way" that will help you avoid some of the same mistakes I made when first starting out. Cast bullets can be (and often are) more accurate than jacketed bullets. You just can't drive then as fast.
Follow this link to the article:

Cast Bullets in the Lee Enfield Rifle