I have a 10 inch SSK stainless barrel with a .311 bore and a friend of mine has a rechambered factory 30 carbine with the 308 bore. He is very happy with his and I think mine is one of my best barrels, as long as you accept JDJones instructions that come with the barrel: NEVER EVER EVEN ONCE FIRE FOREIGN OR SURPLUS AMMO IN A CONTENDER. But it goes on to say that US made or ammo with load data taken from a modern US reloading data is completely safe. I have fired winchester, remington and federal ammo from my barrel with very good results but I reload it mostly for it. I use .311 bullets and find it to be a very accurate round. Brass is avialable for free if you pick it up on most ranges. I actually use 30 herret data to reload with...if you think that's crazy, run a 30-30 shell into a 7.62x39 die and then compare with a herrett...other than the shoulder angle, they are nearly identical...and I know the Herrett data keeps me below 45,000 pressure units. Don't go near anything with steel cases!
As some above have said, not much better than 30-30, but something different to play with. Hey, If JDJones will sell it, it has to be safe...and hey, the guy advertises here so don't be afraid to give him some business!
good luck and regards,
graycg