Throat erosion = re-ream and re-headspace to keep old barrel?

[curseyou]

If I understand things correctly, the main cause of shooting out a barrel is throat erosion. Instead of rebarelling every time, is it not reasonable to re-ream the barrel to dig a new throat deeper into the barrel and then the headspace to the new chamber?

Seems to me these both need to be done with mew barels anyways, but this saves you the cost of a new barrel. (At least once maybe more). I get that you would be shortening the barrel each time, but I get the feeling it is a small tradeoff because even a new barrel would need a new load build up. In my mind, the only downside would be the loss of velocity.

While we are at it, if you could buy a longer barrel than usual, could you do this a few times before your rifling wears out?

Anyone try this? Good/bad/terrible idea?

 

[BigUglyMan]

Depends how much throat is cooked in the old barrel. Eventually you will run out of shank, depending on the profile of the barrel.

 

[guntech]

If you are spending money to cut an inch off an old worn barrel to try and get a few more rounds, you are wasting it... spend the same amount of money towards fitting a new barrel. The labour can actually be more redoing the old barrel.

 

[curseyou]

Depends how much throat is cooked in the old barrel. Eventually you will run out of shank, depending on the profile of the barrel.

Good point. Lots of the heavier profiles could be full for the first 8 inches.

 

[curseyou]

If you are spending money to cut an inch off an old worn barrel to try and get a few more rounds, you are wasting it... spend the same amount of money towards fitting a new barrel. The labour can actually be more redoing the old barrel.

I dont follow. A new barrel needs to be chambered and heasspaces and threaded anyways. My proposal only removes the cost of the new barrel. I read everywhere that when a barrel starts to go, it is not the rifling, it is the throat. Sites like kreiger speak to this being around 10k rounds for .308 and as little as 2k rounds for 300win or 338 lapua etc... These figures speak of throat erosion.

I havent found any numbers for rifling erosion. But if you could get 10 out of the original thoat, and recutting a new throat could give you a new 10k, I think the savings would be worth it. If you could get 3 10ks by doing this twice even better.

A new kreiger barrel blank is 400+. What would just the labour run for a smith to recut a new throat? My guess is the cost could make it worthwhile. Heck there may even be enough merit to using hand tools to diy the throat recuts.
ht tp://m.youtube.com/watch?v=fVJo2i3hyvE

If there are hand tools to cut crowns why not hand tools for headspace?

 

[Alpheus]

If you cut back and re-chamber, you will be lucky if the barrel lasts 50% longer. You won't get 300% barrel life with any kind of respectable accuracy.

 

[tiriaq]

I do my own work, so the labour cost is irrelevant. I have set back and rechambered barrels. The set back barrel will probably not last as long as the barrel did when new.
But as has been pointed out, if you have to pay to have the barrel set back, rebreeched, threads cut, and chamber cut, it probably doesn't make sense.

 

[wasrupzuk]

If your a talented machinist or gunsmith and its your gun and your bored, sure what the hey...
If your paying for labor of a talented machinist or gunsmith then guntech just answered your question.
Sometimes you can trip over dollars picking up dimes.

 

[guntech]

I dont follow. A new batrel needs to be chambered and heasspaces and threaded anyways. My proposal only removes the cost of the new barrel. I read everywhere that when a barrel starts to go, it is not the rifling, it is the throat. Sites like kreiger speak to this being around 10k rounds for .308 and as little as 2k rounds for 300win or 338 lapua etc... These figures speak of throat erosion.

I havent found any numbers for rifling erosion. But if you could get 10 out of the original thoat, and recutting a new throat could give you a new 10k, I think the savings would be worth it. If you could get 3 10ks by doing this twice even better.

A new kreiger barrel blank is 400+. What would just the labour run for a smith to recit a new throat? My guess is the cost could make it worthwhile. Heck there may even be enough merit to using hand tools to diy the throat recuts.
ht tp://m.youtube.com/watch?v=fVJo2i3hyvE

If there are hand tools to cut crowns why not hand tools for headspace?

As far as how many rounds you get out of a barrel - it all depends on what kind of accuracy you are happy with...

To dial a bore in and chamber and thread and fit a new barrel blank using the most accurate methods can cost $250. It is more work to do the same to a worn barrel by cutting off an inch.. and any accuracy gain (if any) wont last long. I know of a serious Benchrest shooter who does his own work and he sets his barrels back 1/4 inch and cuts a fresh chamber every 400 rounds or so. Crowns can be refreshed every 400 rounds as well.

You ask, If there are hand tools to cut crowns why not hand tools for headspace?

There is one tool to start with - a hacksaw to remove an inch of the barrel... but explain how any hand tool can be substituted for a lathe and the skill to use it to finish the job.

I have cut off and re chambered worn barrels for customers... but I won't do it any more because result have shown it is a waste of money and I feel bad about charging for it.

 

[bearhunter]

First off, you have to determine how far out the throat has been pushed. I have seen some barrels where you would have to remove 5-8cm to completely clean up the erosion. If it is a heavy barreled rifle it might be fine to do this and get it to where the rifling and leade are as new or very close to it. I have done this with a few match grade barrels that were used in competitive shooting. Often these barrels have less than a couple of thousand rounds through them.

Heavy barreled factory sporters or Varmint rifles on the other hand have definite profiles and just might not have enough meat to safely make such an alteration.

If you are trying to make up a varmint rifle as has been mentioned before, setting back the barrel/recutting the threads and rechambering might be fine for your purposes as long as you aren't planning on putting another 7000-8000 accurate shots downrange. I haven't seen many hunters that have shot out a barrel by themselves on a hunting rifle.

If you are planning on extending the life of a match rifle to end a season or see if you can stand the rigors as well as the expense of match shooting MAYBE.

If you are building a match rifle and trying to do it on the CHEAP, forget it. It is a fruitless endeavor and a very false economic gesture.

If you have to get the work done, start with a new barrel.

One other bit of advice, just because a barrel isn't built by Shilen/Hart/Kreiger doesn't mean it won't shoot well, even on a competitive basis.

One of the most accurate rifles I have every owned has a Green Mountain barrel on it that cost less than $200 shipped to my door. The new machinery used to make these barrels is state of the art and your chances are just about as good at getting a potentially accurate bore as one of the extremely expensive offerings.

I have been very pleased with Green Mountain offerings even though I was very apprehensive with the first couple. The latest is going onto a Ruger No1 that is presently wearing a GM barrel that has had a few thousand 338 x 225gr Hornady Spire points in a 338-06 through it and is still very accurate. I can no longer take the recoil of this lovely combination so it will become a 280 Rem with a 27in finished length barrel.

I don't like spending any money I don't have to. My wifey married a tightwad. But it certainly didn't take very long watching guys at matches trying to save $50 and being frustrated with the results of trying to salvage a barrel with a washed out throat.

 

[sunray]

A shot out barrel is a relative term. Means one thing to a hunter, quite another to a bench rest shooter. A hunter will very likely never shoot out a barrel in his entire life. A BR guy thinks one is shot out if his groups get bigger than the calibre he shoots.
Anyway, the length of the barrel means squat. It's the length of the threaded shank that matters. If you buy a new barrel, it'll most probably be for a given rifle and will have a threaded shank vs a barrel blank that's just a rifled pipe. Then there's muzzle wear.
Epp's rebarrels with a blank for $225 plus the cost of the barrel. $150 for a threaded, contoured, short chambered barrel.