Gunsmithing Setting a barrel back

[264shooter]

My 308 has around 4000 rounds through it and it just does not group as well as it use to.

Is it worth the time and money to set a barrel back and rechamber it just to save on the expence of a new barrel.

 

[bcjolly]

Re: Setting a barrel back

I asked this question of Fred Sinclair of Sinclair International some time ago. His answer was if you're going to set a barrel back, do so before 2000 rounds, otherwise spend the money you would have spent on the barrel setback to buy a new barrel. My personal gunsmith also told me about the same thing. Barrels don't last forever. My only problem is in finding one that shoots as well as the last one. Best of luck.
Barry C Jolly

 

[Victor N TN]

Re: Setting a barrel back

If you can do it yourself and do it right, then try it. If you have to pay someone else to do it... I wouldn't do it. Something else to think about. If it's a factory tube I would just use it for a spare and get a new barrel with the chamber I wanted in it.

 

[918v]

Re: Setting a barrel back

Barrels wear at the throat and at the muzzle. I vote get a new barrel.

 

[Hateca]

Re: Setting a barrel back

Check the crown. (And not by simply looking at it either. Use a bore scope and look at it from the inside) Having it re-crown could just possible fix your issue and may have nothing to do with setting the barrel back.

If this is a factory barrel don't even bother with the set back at 4000. If this is a custom barrel and you ran it without pushing the pressure then a set back might work but 4000 rounds I would lean towards a new barrel since I have seen barrels run hard and only last 5000. Not worth the chance.

 

[yavapai kid]

Re: Setting a barrel back

I say do it to and find out how it does.

You might get another 1,000 or 2,000 rounds out of it.

Then maybe not. It's not an expensive lesson.

Then you can give the rest of us a real answer.

 

[shooter65]

Re: Setting a barrel back

set back and crown. never do one without the other.

 

[264shooter]

Re: Setting a barrel back

The rifle is my Surgeon with a 26" MTU Kreiger that was chambered with a Palma 95 reamer.
I can have it done locally and we have a palma 95 reamer.
This rifle was a real shooter and I think it would be a good experiment.
If it doesn't work then it will be time for the 6.5 barrel.
The only thing that haunts me about this is moving away from the 308.
I go way back the 7.62

 

[Hateca]

Re: Setting a barrel back

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 264shooter</div><div class="ubbcode-body">The rifle is my Surgeon with a 26" MTU Kreiger that was chambered with a Palma 95 reamer.
I can have it done locally and we have a palma 95 reamer.
This rifle was a real shooter and I think it would be a good experiment.
If it doesn't work then it will be time for the 6.5 barrel.
The only thing that haunts me about this is moving away from the 308.
I go way back the 7.62 </div></div>

Custom barrel then it won't hurt to take a chance if the price is right and you kept it in the pressure curve.

You go to a 6.5 barrel you will be replacing barrels a lot sooner then that .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shooter65</div><div class="ubbcode-body">set back and crown. never do one without the other. </div></div>

Never is such a strong word.

Don't agree, I've seen new factory barrels with screwed up crowns. Cutting a new crown can do wonders for barrels accuracy.

If someone has a damaged or worn crown why would they necessarily need to turn the barrel back?

Lots of guys will re-cut a crown after X amount of rounds whether they think it needs it or not.

Cutting a new crown is not what one might think. You're not removing lots of metal when re-cutting a crown. A better word might be refreshing a crown.

 

[Victor N TN]

Re: Setting a barrel back

+1... what Randy said.

On the 10" South Bend lathe I can recut the crown without pulling the barrel. (On a 20" or longer) Just take the scope off and the stock off.

I try to recut the crowns between 300 and 500 rounds. The benchrest barrels sooner than that.

 

[wnroscoe]

Re: Setting a barrel back

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 264shooter</div><div class="ubbcode-body">My 308 has around 4000 rounds through it is it worth the time and money to set a barrel back and rechamber</div></div>

I did this very thing on a 6BR after 2,500 firings. I completely cut off the threads and chamber, about 3" worth of barrel. I completely re-machined the tenon and cut a new chamber. I should have cut an additional 1" off the barrel as there was still fire cracking in the neck of my new chamber. The barrel shot great and the match grade accuracy returned but, a barrel that's set back will only last about 50% as long as it did when new. I was able to do this and justify the cost as it was my barrel and the cost was only my time and reamer wear. Would it be a wise investment for someone that has to pay? Probably not as you'd only be saving the cost of a barrel and receiving a 50% use rate on said barrel. With 4,000 rounds down range pin point match grade accuracy has long been gone. I'd opt for a new barrel and installation.

 

[zenbiker]

Re: Setting a barrel back

At 4000 rounds, get a new barrel. Save the old one and maybe send it to Krieger to be rebored and rerifled to a .338

There will be a lot of heat cracking in the lands and grooves; barrel life from a set back barrel is usually less than 1/2 the life of the original barrel.

Yep, time for new steel.

 

[AUJohn]

Re: Setting a barrel back

How do you clean it?
Give it a REALLY good clean and crown then see how it goes.
Seat out and test.
4K is not a lot out of a 308. It's not unusual for them to go a lot longer than this so before you do anything try what I said. If it's still bad I would rebarrel.


How much accuracy did it drop?

 

[264shooter]

Re: Setting a barrel back

When it was new it was a solid .5 minute gun, now 1 inch has been the norm lately.

 

[One-Eyed Jack]

Re: Setting a barrel back

Borescope it carefully to see whether it has a problem that can be fixed without machining anything. Carbon build up is one possiblity, and copper another.

264shooter, where are you located in "western NV"?

 

[AUJohn]

Re: Setting a barrel back

It's not unusual for a "bad" looking barrel to still shoot ok.


How do you clean it?

 

[zenbiker]

Re: Setting a barrel back

4K is a shiteload of rounds for anything but a minigun. If you want to go through the undertaking of removing the barrel, break bad and put a new one on it. On average, a setback barrel will give at best 1/2 of original barrel life. At best.

Just sayin.

At any rate, best of luck with whatever you do, mate.

Regards,

Wes

 

[Goatman007]

Re: Setting a barrel back

As a rule of thumb, 4-5K from a regular barrel, 25-30K from a chrome lined bore.

 

[jarheadkp]

Re: Setting a barrel back

A 95 reamer is short throat-ed for 155's. 4000rds would be a good life for a palma rifle using the 155's, but might have more life with a heavier bullet. What twist do you have on that barrel? I would Vote to have it re-crown just because gases can distort the crown just from that many firings, I had an M1A re-crown and was able to restore accuracy for another 1500rds.