If you are going to shoot at 1000 yards, don't use a .308. If it was the best round for that then the long shooters would be using it, and they dont.
Tubb knows what he is talking about and has the winnings to prove it. When he shows up to a match everyone else fights for second place. His 6mm is an exellant long range cartrage, but there are others as well. Many people use the 6.5x284 since the heavt 6.5 really hols its velocity at long range. There are other choices as well. Is Tubb making money off of his ammo and gear? yes, but he has used it himself and knows what he is talking about. Now the real question you should be asking is are YOU skilled enough to use this gear to its full potental.