Ball life estimates contain a whole bunch of variables: definition of accuracy, serviceability, ammunition used, maintenance, etc.
When I used to work on light armoured vehicles, the barrel life on the M240 7.62 NATO caliber machine guns were considered to have a barrel life of 20,000 rounds. The current service rifles M16A2 and M4 series are considered to have 20,000-30,000 barrel life between replacements.
Submachine guns in 9mm and .45 ACP can show extreme barrel throat wear and still be very serviceable. Their barrel lives are measured in the several tens of thousands of rounds.
When I used to hang out with Navy small arms armorer types, the word was that match-conditioned M1911A1 pistol barrels were considered competition quality up to 5,000 rounds. The service ammo fired then was 230 grain ball using guilding metal clad steel jacketed bullets for service pistol competition. I remarked that it was quite a number of rounds, and the armorer guys said that was typical barrel life for TWO accurizing rebuilds.
In my limited experience for PPC shooting, two seasons and over 50,000 rounds of 38 Special lead wadcutters never affected the accuracy potential of my M19.
For sporting use, I doubt if an individual is likely to wear out a .357 or even a .44 Magnum barrel. Silouette competition is another matter, however. In that game, battering actions loose, out of time, and flame cutting of breech throats is what wears out revolvers.
When the S&W 500 first came out, owners were dismayed to discover that the mfr stated that barrel life was 1200-1500 rounds between replacement! I don't know if the situation has changed, but that sounds pretty extreme.
