It has been a long time since I read it BUT the first figures that I heard went 8,000 to 10,000 as the expected life of a barrel. It does vary with the cartridge used however. My .222 Remington was used by a previous owner to the point that the barrel had to be shortened and rechambered. Don't know how many rounds he put down it but I have put at least 2,000 rounds through it.
