.308 and barrel life


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clutch
July 24, 2011, 06:44 PM
Lets say one buys or builds, or tweeks a .308 to .5 moa to .75 moa. How many rounds would it take to turn it into a .75 to 1.0 moa rifle due to barrel erosion?

Are there barrel materials that have longer life than others?

For 100 - 800 yards, with barrel life being a criteria, is there a better cartridge?

Thanks,

Clutch

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animator
July 24, 2011, 07:17 PM
A lot of that is going to depend on the barrel manufacturer, as well as the ammo (handloads) you are shooting. High-velocity handloads can wear a barrel out in a thousand rounds, where moderate loads can run for a few to several thousands before the barrel needs to be replaced.

bigedp51
July 24, 2011, 07:38 PM
At 43,000 cup the peak flame temperature is just reaching the melting point of modern barrel steels. The higher the peak pressure the more bore erosion, my 30-30 Winchester barrel will out live a few owners at a maximum chamber pressure of 38,000 cup.

More barrels are ruined by improper cleaning methods than bore erosion and that is why I use foam bore cleaner, and spare the rod and spoil the barrel.

nastynatesfish
July 24, 2011, 07:39 PM
Not really any reason to push a 308 past 2900 gps with match heavy bullets. I'm buildin a 308 now off a 98 mauser its gonna be a dual purpose targe/hunting rig. Unless your shooting for money the 1/2-1 moa won't hurt anything.

taliv
July 24, 2011, 07:46 PM
If you aren't rapid firing it you should get 5000-8000 rnds before the groups open up

260rem 6.5x47 and 6.5 creedmoor are all better choices

clutch
July 24, 2011, 08:00 PM
If you aren't rapid firing it you should get 5000-8000 rnds before the groups open up


I can live with that number.


260rem 6.5x47 and 6.5 creedmoor are all better choices

I thought the 6.5's were barrel burners. Are you telling me they have better or equivalent barrel life in respect to the .308?

Thanks,

CLutch

mrbro
July 25, 2011, 12:02 AM
At 43,000 cup the peak flame temperature is just reaching the melting point of modern barrel steels.

That is probably the single most important fact I have ever seen posted on this subject. Thank you for that.

Z-Michigan
July 25, 2011, 12:47 AM
You won't find any definitive answer to your question. Far too many variables in terms of both how group sizes relate to barrel wear (which depends heavily on the type of steel used, among other things) and that the barrel wear will vary considerably with your style of shooting.

Are there barrel materials that have longer life than others?

Yes, the current champion seems to be hammer forged barrels with chrome lining. I can already hear all the "not accurate" claims, but FN Herstal, Steyr, and probably a few others make hammer forged, chrome lined barrels that consistently deliver sub-MOA accuracy, including in .308 Win.

The other interesting barrel material/construction is nitrocarburizing treatment on appropriate carbon steel (comparable to the "Tenifer" on Glock barrels and slides, or to "Melonite" which is simply a brand name for a particular form of this process). I believe AI and several other European makers use this approach but I am not certain. It appears to deliver similar excellent durability, but there just doesn't seem to be any rigorous empirical proof in the public domain.

For 100 - 800 yards, with barrel life being a criteria, is there a better cartridge?


A .45-70 can easily reach out to 800 yards and will likely last for a lot more shots fired - but the necessary precision of your elevation and wind compensation would be a little more challenging than with a .308!!!

TonyAngel
July 25, 2011, 03:55 PM
With a .308, barrel erosion isn't what you have to worry about, so much as throat erosion. According to my smith, I should get a good 5000 rounds out of my barrel, then I can have him cut it and rechamber it to get rid of the eroded throat. I should then be able to get at least another 5000 rounds out of it.

Zak Smith
July 25, 2011, 04:02 PM
I have about 6000-7000 through my original AWP barrel and it still shoots sub minute, and about as good as it was when new. I expect to get about 10k through it.

The .260 will give you better ballistics at maybe 50% less barrel life. For me and many others, it is the sweet spot of ballistic performance vs. barrel life.

clutch
July 25, 2011, 05:57 PM
With a .308, barrel erosion isn't what you have to worry about, so much as throat erosion. According to my smith, I should get a good 5000 rounds out of my barrel, then I can have him cut it and rechamber it to get rid of the eroded throat. I should then be able to get at least another 5000 rounds out of it.

Excellent point. I didn't consider that.

Thank you for pointing that out.

Clutch

bigedp51
July 25, 2011, 07:20 PM
clutch

1. Where did you think erosion started at, the muzzle or throat?

2. If you have a tapered barrel like the majority of us have, just how far do you think a barrel can be setback or shortened and re-chambered for your .308?

Throat erosion is governed by chamber pressure and powder burning rate and more barrels are damaged by improper cleaning methods than any other cause.

The target below was fired at 50 yards with a 68 year old .303 Enfield with cordite throat erosion and iron sights. Cordite powder has more nitroglycerin than many double base pistol powders have today and caused more throat erosion than any rifle powder we have today.

http://i122.photobucket.com/albums/o254/bigedp51/range-day-2-1.jpg

I just sold off many of my Enfield rifles so I could buy new rifles with tight chambers because I wanted my "brass" to last a long time.
(the last thing I'm worried about is bore erosion because its going to happen on any rifle above 43,000 cup)

If your worried about throat erosion buy a 30-30 or a cartridge with less than 43,000 cup chamber pressure. Your barrel erosion will be governed by how "HOT" your loads are. AND your loads will be governed by how accurate they are and accuracy trumps bore erosion.

Bottom line, pick your favorite cartridge and shoot it till you need a new barrel. :what:
(its not the age, its the miles) ;) and how hard the mileage was :eek:

If your still worried about throat erosion after read above then join the Savage/Stevens barrel nut club and change your own barrels. ;)
I wanted a .308 but settled for a .243 with more bore erosion than the .308 but thats what happens during a sale and they run out of .308, and I'm not crying about it.

http://i122.photobucket.com/albums/o254/bigedp51/IMGP6475.jpg

243 Win Cartridge Guide
High-Velocity 6mm for Long-Range, Varminting, and Tactical Use
http://www.accurateshooter.com/cartridge-guides/243win/

RickMD
July 25, 2011, 07:25 PM
Unless you're one of those guys who have to shoot maximum, screaming hot loads all the time, expect 3000 to 5000 rounds with a .308 before you notice a miniscule bit of difference in accuracy. The U.S. Army armors thought that barrel life on an M-14 was around 8000 rounds and that's a rifle with full auto capability. That's a lot of shooting.

It all depends on the quality of the barrel, break in, rate of fire, and cleaning as well. I've got a Shilen premium grade stainless on a 98 Mauser with about 11,000 rounds through it and it still holds less than one MOA.

clutch
July 26, 2011, 08:24 PM
I guess I should have said throat erosion when I first posted. Outside of cleaning rod damage or wacking the muzzle and damaging the crown, the throat is where the wear is.

Clutch

Get R Done Guns
July 26, 2011, 09:34 PM
You should see at least 4,000 rounds or so before having to look at setting it back if you shoot a Med-high loading. If you shoot hot loads, start looking about 1,800 rounds. Clean it well and don't run the pressures to high it will surely break the bank before the barrel goes. :)

TonyAngel
July 27, 2011, 02:00 PM
Clutch, what sort of shooting are you planning to do with the rifle? Personally, I love .308. Long barrel life, brass is plentiful, wide choice of bullets and it seems to have an inherent accuracy. It's also flexible enough that it can be used as a good compromise caliber for long range shooting, but it is in no way the best for long range. It'll do it, but just isn't the best choice for the job.

Do you handload? If so, this will make it easier to tailor ammunition to your rifle and allow you to sqeeze more performance out of your rifle.

prism
July 27, 2011, 06:55 PM
has anyone thought of the cost-per-shot, wrt barrel expenses?

big round numbers, $500 for a premium barrel, gunsmithing, and some load workup costs.

5,000 round accuracy life.


each shot costs you ten cents.

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