I am in the market for a new barrel. I am leaning toward a Lilja in a .308 sendero contour. The part I am having trouble with is the grooves. I have no idea the pros and cons of the too. I am currently shooting 230 Bergers with very good success with a factory 26' barrel. I need your help....please explain the difference and the best choice for selecting a appropriate groove for a 28' sendero barrel. Thank you very much!