I tried to answer this earlier but it didn't post, Huh?
What I said was this is the 64 thousand dollar question... How long will a barrel last, how good will this barrel be?
There are many answers to that question and many ways to word that question. In competitive "Point Blank" Bench rest,,which is where I am, 100, 200, and 300 yard formal and informal matches), the barrels are mostly for 6 PPC and 6 BR, also slight numbers of .22 short PPC, and .30 BR. These barrels last as long as they are competitive. Meaning if I have a barrel on my gun that won't agg with the best of them, why am I trying at this shoot. That being said, the barrels don't last very long. Some barrels are no good after 800 rounds, some never were any good, some last 2500 rounds,.30 Br being the exception there). Some of the thirties have been known to last 8000 rounds. That is the barrel on your rifle for competition purpose only...
If you plan on doing live varmint hunting the barrel is by all means good for that for a number of more rounds.
If you are buying a barrel for long range competition,something I am new to) you can get a barrel 31 to 32 inches long finished length. By doing this you optimize the burning of slow powder behind long bullets. When that barrel is shot out,6BR), which will last a lot longer than in point blank BR,,less accuracy demands), you can have your rifle smith set the barrel back a few inches and re-chamber. Now you have a 29 inch or so barrel still long enough for optimizing the slow powder and long bullets. The other thing is now you have a barrel that you know was good,was it?), and the barrel has been cared for,was it?) and it is lapped in with your rounds, from the first go around. Many "long range" high power and F-class guys are doing this. It lengthens the usable time for the barrel. after a few times doing this the barrel will be short enough that you don't want to do this anymore, but they are still accurate for Varmints.
Barrels, when you find a good one, make the most use of it. Don't waste ammo and time with a barrel you know is no longer competitive. Odds are the barrel is burnt in the first inch or so from the chamber. If there is plenty of length, re-chamber it. If not use it for something else.
A lot of Point Blank BR guys have gone to Moly or Danzac on their bullets. I have moved over to Danzac, I find that using it I can return to the same impact point after cleaning sooner, and the barrel shoots cooler,doesn't heat up as hot or as soon). Also during a aggregate,5 matches) I don't have to give as thorough a cleaning to the barrel. What I do is between matches I clean with 2 patches of GM top engine, then 2 dry patches, then 2 patches of penephite,lock ease type suspended graphite). This cleaning helps get the powder fouling out, and preps the barrel for the next match. I can do this all day,10 matches) or two aggregates. At the end of the day I clean basically the same way but I brush with the GM Top Engine Cleaner in the Barrel then flush with 2 patches before going to dry patches. By doing this and cleaning properly you can definitely extend the life of your barrel.
Hope this helps...
I can't for the life of me figure why the last time I typed this it didn't post.
Pbike