I get questions about this, so here’s a brief guide:
It’s impossible to say, flatly, how long a barrel will last. Even after it loses its peak accuracy, a barrel will often remain perfectly usable for a many rounds more. Here are some rough estimates from a gunsmith friend of mine who is anguished because I’m not listing the dozen or so qualifying factors that go into how long each of the following will last. The numbers below refer to the very best accuracy of which a tube is capable, before it starts to slide even the smallest bit.
- .22 Long Rifle: 250,000 rounds.
- .22/250: 1,000 rounds
- .243: 1,000 rounds
- .270 Winchester: 1,200 rounds
- .308: 3,000 rounds
- .30/06: 2,500 rounds
- 7mm Remington Magnum: 1,500 rounds
- .300 Winchester Magnum: 1,500 rounds
Remember that these are very conservative figures. You can have a minute-of-angle .270 that erodes until it only (!) shoots a minute and a half, and it is still an eminently usable rifle. More coming with the next rant.