That really depends on a lot of factors:
- What kind of loads are you running through it? Max loads, or moderate to mild loads?
- How are you treating the barrel? Are you shooting it until it burns your hand to the touch, or does the barrel never get hotter than "warm"?
- What is your definition of "shot out"? When accuracy opens up wider than 0.5MOA, do you trash the barrel and order a new tube, or do you consider a barrel that still shoots 2MOA to be running strong?
Depending on the answers to these questions, I would expect somewhere around 800-1000 rounds if you're shooting F-Open, and 1500-2500 if you're satisfied with 1MOA groups and use the rifle for hunting and casual plinking.