IMO, the 6mm AI is about max as far as 6mm cartridges go. You won't do a thing but shorten barrel life with any case larger. Very forgiving, accuracy wise, during fire forming and at its' peak with 100g. + weight bullets. If you're thinking of re-chambering a factory barrel, I have to ask, Why Bother? You've got to realize, it's not just throats that wear, but the full length of the barrel that does, starting at the throat. 95%+ of the barrels I see that the owner wants me to re-chamber are long past that point of improvment. Much of what it's seen on the forums these days has been tried, some of it long ago. If it hasn't "caught on", there's a reason.