Shot-out barrel: Shorten and rechamber?

[Syncrowave]

After a barrel is shot out, eroded and not shooting well anymore, I'm curious whether it's worthwhile shortening the chamber end a couple of inches and then rechambering.

Does getting rid of the eroded throat typically give you a like-new barrel crap shoot, as far as accuracy?

Or does the wear, fire-cracking, etc., normally affect the entire length of the bore?

I'm new to the whole issue of shot-out barrels. I have a 270 that may be getting shot out, but am not sure yet. Trying some JB which removed a LOT of black stuff, even after I thought it was "clean," but haven't shot it yet to see if accuracy was restored.

Somewhere I read that when a barrel gets shot out, it starts copper-fouling real bad, which leads me to believe the wear and damage are thoughout the whole bore, and that shortening and rechambering may not do much good.

Would love to hear any insights from those of you who have gone through this and maybe tried it...

Edited to Clarify: My question mainly concerns rifles chambered in overbore cartridges like 6.5/284 or .22-250 that would normally start to go downhill after one or two thousand rounds rather than tamer chamberings, like 222, that might get several thousand rounds before losing accuracy. I suspect that by the time those barrels lose accuracy, they would be much more worn down the entire length of the bore, as compared to the overbore chamerings, which I suspect would have most of the wear and accuracy-degrading damage closer to the throat...

 

[jonbearman]

How many rounds down it would dictate a rechamber.As long as it still shoots fairly well it may be worth it.If it has alot of rounds on it,get a new barrel.

 

[Jay Christopherson]

My own experience with setting back a match barrel was that it did shoot better - for a short while (in match barrel terms). I got about another ~500 rounds out of it which wasn't worth the effort IMO as by the time I re-calibrated my load, and shot a match with it, it was pretty much done.

On a hunting/sporter rifle though, I think it could be worth it. I don't go through 20 rounds a year on those (after the initial load development) and if I could set it back and get another 500 rounds (or more) out of a barrel, I think it would be worth doing.

My *guess* is that the wear and tear due to heat has something to do with the utility of the process.

 

[watercam]

In scoping two shot out over-bore barrels (one 6.5/284 and one .243) the firecracking, pitting, etc. extended for 8-10" beyond the throat area.

 

[wapiti25]

First if you do your own chambering the cost is your time. Second if you want to set a barrel back it is best to do it before the barrel is "toast", then you can get a reasonable renewed life. I have done three or four barrels and found that they may not be as good as new but shot better and less copper fouling than before. A 6.5-284 should be done at about 800 rounds. I have a 6.5-06 that has about 1500 rounds and it is fire cracked for about 4" or 5". I would only set back for accuracy if I could chamber ahead of the fire cracked area. I'm shooting a Krieger barrel that was used and re-chambered in 223, that has 600 rounds and shoots good at 600 yds but it is showing fire cracking for the first .100". My bore scope is my friend.

 

[X Ring Accuracy]

As said above. If a hunting rifle, yes. If you do your own work, yes as it is only your time. If a target / match gun that you pay someone to work on, get a new barrel as the gamble can roll against you.

 

[shortgrass]

The barrels I get to see for "setting back" and re-chambering fall into two groups,,,, A; they're so worn out it makes no sense to put one thin dime into them, or B; there's not enough shank to work with.

 

[TAJ45]

Mini Hi Jack here and I think I know the answer but will give it a toss into the ring anyway.

22-284 with 600+ on it. Used for 1K matches and winning enough. Good enough for F UNL if rechambered for .223?

It is a Lilja 8tw and 28 1/2" from brake shoulder to lug shoulder.

I know, a borescope would tell the tale. I am pretty much a newbie for the BR type stuff so I'm hedging that if the gen'l consensus (with no bore scope available) says I could get another 600 out of it, maybe worthwhile? I guess for a rechamber/crown etc that would figure out to be around 50 cents per shot if that much life left? When I put it that way, it really makes one think.

 

[Syncrowave]

Thank you for the replies, fellas. I guess the best bet with an overbore cartridge is to go with a new barrel...