This thread took an odd turn.
I don't think I would gauge barrel life on the experiences of anyone firing 300+ rounds a day, regardless of the context. The barrel doesn't care what you're shooting at. It would be just as useful to hear from competitive shooters who've shot monos and lead core bullets.
I have a buddy who's a PRS shooter and burns through 2-3 barrels per season. I'll ask him if he's ever had a barrel that he shot monos in exclusively. David Tubb would be another person with some possible experience on this topic. I know he used the Flatline bullets in his XC rounds, but I don't know if he uses them exclusively. Both of those scenarios are competitive shooters though, so it may not be relevant to hunting rifles.