How many rounds to wear out a barrel?


PDA






rocinante
March 8, 2011, 01:01 PM
I have a green mountain 4140 chrome moly 7.62x39 barrel, non chrome lined, 1 in 9.5 twist rate, reportedly between 30 and 35 rockwell C hardness.

If it is cared for, i.e. cleaned after shooting but not abusively, how many rounds should it go before accuracy becomes affected?

If you enjoyed reading about "How many rounds to wear out a barrel?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
mc223
March 8, 2011, 01:07 PM
There is no right answer to your question. Too many variables.

rocinante
March 8, 2011, 01:14 PM
mc223 I tend to agree but it hasn't stopped folks with chrome lined barrels in the same weapon saying everything from 1 30 round mag to 1K rounds and I got a paper weight. Just thought I would ask the grown ups here.

rcmodel
March 8, 2011, 01:16 PM
+1

Barrel life is determined by rate of fire/heat more then anything else.

If you have sixteen 100 round C-Mags and do a lot of bump fire mag dumps, you can ruin a barrel several times faster then if you don't.

At any rate, the 7.62x39 is not noted for being a barrel burner, or even especially accurate in most of the firearms it is used in.

I'd have to say the cost of the ammo to burn out your barrel would be many times over the cost of replacing it if you ever have too.

So don't worry about it.

rc

M1key
March 8, 2011, 01:32 PM
^^^what rc said.

22 LR?...maybe a lifetime

Benchrest shooter?...maybe 1500 rounds.

With today's ammo costs, most folks probably could not afford to wear their barrels out. Shooting to the point where accuracy begins to fall off would depend on caliber, velocity, operating pressure, bore cleanliness, even type of rifling, etc.

rocinante
March 8, 2011, 01:36 PM
With today's ammo costs, most folks probably could not afford to wear their barrels out.

true dat

rocinante
March 8, 2011, 06:09 PM
I am getting votes but no comments so I thought it was dead. Thank you for your feedback and vote.

WNTFW
March 8, 2011, 06:33 PM
FWIW the Highpower crowd budgets about 4,000 rounds before they figure the barrel starts to affect the 600yd scores. Maybe you can push that to 5 or even 6k. These are primarily .223 AR's. Then they use that upper for short line practice & matches.

I get conflicting views on what are known "barrel burners". I think the abuse or care taken with a barrel matters.

newfalguy101
March 8, 2011, 06:42 PM
Based on your critera of being "cared for" I voted for 20,000+ as the X39 is NOT a high pressure, nor a screaming fast cartridge, add in the fact that its not known for accuracy ( although I believe it can be very accurate given a good barrel and bullet ), I dont think you would notice any appreciable difference in accuracy for quite some time, and even then, at what point is it "shot out", at what point is accracy so bad you would rebarrel??

Al Thompson
March 8, 2011, 07:32 PM
I voted before reading about the cartridge. Oops on me. The more powder you light off, the more you burn the barrel. The late great Gale McMillan used to write that firing a shot was very similar to flickering an oxy-acetylene torch in the chamber. Obviously the more you flicker that torch, the more the barrel will be effected.

From my reading in Precision Shooting, Sierra felt that their .308 test barrels usually went out of tolerance at (IIRC) about 7-10 thousand rounds downrange.

BrocLuno
March 10, 2011, 05:53 PM
Depends on caliber and charge? 22LR - maybe 100,000 or something? What are we talking about here?

W.E.G.
March 10, 2011, 06:10 PM
You need to state how the barrel will be used, and what are your criteria for accuracy failure before this question can be answered in any meaningful way.

The cartridge cited is a low-pressure, .30 caliber cartridge.
Fired in a bolt gun and the sort of pace usually used for that sort of gun, I would estimate your group sizes would double by the time you fired 20,000 rounds.

So, if you shoot 50 rounds every single week for 7 years, you'll probably start to notice the drop-off in accuracy. Nobody shoots that much - or anything close to it - from an x39 bolt gun. That means you won't live long enough to see the accuracy drop off enough to matter.

Ky Larry
March 10, 2011, 06:19 PM
Wouldn't the type of powder and bullet used be major factors? Don't some powders burn hotter than others? Would moly coated bullets prolong barrel life?

61chalk
March 10, 2011, 07:28 PM
Well the GCA took a M1 Garand an had to fire it 7000 rds. to go down 1.0 in MW....assuming a new barrel is MW 0.....it would take 28,0000 rds to get to MW 4.0, an I've read where guys are still getting great accuracy out of Garands with MW 4.0....Its hard to believe CGA took 7000 rds to get down 1 MW.....that means my Garands have been fired about 14,000 times....this just doesn't seem possiable.....I also heard somewhere that the average barrel only lasts about 5 seconds....the bullet travels so fast down the barrel, that when you take the time it takes to travel through the barrel times several thousands of rounds it comes out to about 5 seconds....incrediable.

rocinante
March 10, 2011, 10:07 PM
.I also heard somewhere that the average barrel only lasts about 5 seconds....the bullet travels so fast down the barrel, that when you take the time it takes to travel through the barrel times several thousands of rounds it comes out to about 5 seconds....incrediable.

That sounds cool

hps1
March 10, 2011, 10:31 PM
Would moly coated bullets prolong barrel life?

I shot NRA HP competition for many years and shot at least 100 rounds per week, using several different rifles. Shot out four barrels in my favorite bolt gun (it was a 30-06) and they usually started throwing unexplained fliers @ 600 yards somewhere around 7500 rounds. The NM course consists of two rapid fire strings of 10 shots w/60 and 70 second time limit, so the barrels get pretty hot. Regional matches are worse as they shoot 4 rapid fire strings.

The first two barrels never saw a moly coated bullet and the last one shot only moly; the fourth barrel is still going strong at about 4500 rounds. All the barrels had very similar round count when replaced. Barrels wear out in the throat and this wear is caused by heat and friction. The moly reduces friction but can do nothing to block the intense heat and I didn't see any evidence of it extending barrel life. Allowing your barrel to cool between shots and proper cleaning will do more to extend its life than anything else.

Regards,
hm

j2crows
March 10, 2011, 10:32 PM
I never counted rounds in my first .243 Douglas air-guage barrel but, it took me 13 years to go from almost one-holers to 3/4"-1". That rifle accounted for a lot of varmints in it's day.

451 Detonics
March 10, 2011, 10:40 PM
The 7.632X39 is a slow round, even shooting rapid fire it shouldn't cause throat erosion very fast. My 22 CHeetah (vast overbore, .308 brass necked down to .223, 55 grain at 4250fps) on the other hand is good for about 3000 rounds before accuracy starts to suffer.

BigN
March 11, 2011, 06:57 PM
I have many very hot centerfire calibers that I've literally shot many thousands of hot reloads through over the years. I mean hot...not dangerous but very hot. None of the rifles I have have shown any accuracy fall off as of this date. I'm guessing I shoot more rounds per year than 90% of the folks here, and that's a lot. We're talking about a lot of years and a lot of rounds. It's highly unlikely that you'll ever shoot any barrel out. Maybe if you filled the barrel with dirt before each outing.

jazzpicker
March 12, 2011, 12:58 AM
7.62X39 should go nearly forever unless the barrel is not maintained or you get the barrel hot as hell frequently.
Watch out for calibers with big cases with small high velocity bullets if you are worried about short barrel life.

snake284
March 12, 2011, 02:34 AM
No offense meant, but that's a loaded question. That's like asking how many miles will my tires last? That all depends on several factors.

1. What brand of rifle or barrel?

2. What caliber or Cartridge?

3. Handloads or Factory rounds?

4. What do you shoot? Target, varmints, hunting?

5. How many rounds do you shoot per range trip?

These are just a few questions that should be asked. For instance, take number one:
What brand of rifle or barrel is on the gun in question? If you buy an el cheapo for $150 it may not be made of high quality steel. This also applies to barrels. I have heard from a competant gun smith that the Adams Bennet barrels that Midway sells are not as hard as say a Shilen or Lilja and may not hold up as long.

Number two:
What caliber or cartridge is the barrel? For instance you can't hardly compare a 30-30 Win. with a 220 Swift. The Swift is an overbore beast that breaths fire and can burn the barrel out with hot loads in under 1,000 rounds if you're not careful. However, you could probably shoot a 30-30 20,000 rounds before you ever got close to eroding the throat. A 30-06 is not as hard on a barrel as a .270 Winchester, and a .270 Winchester is probably not as hard on a barrel as a .25-06. A 7mm-08 is probably easier on a barrel than a .243, while it's probably harder on a barrel than its parent cartridge, the .308 Win.

It all boils down to how overbore the cartridge is as to how long it will take to shoot it out.

Number three is what kind of ammo do you shoot in it mostly, handloads, factory, milsurp? Some factory loads have been known to be really hot and hard on barrels, such as the 220 Swift. It is very overbore and in factory form in the past it was loaded hot and there have been stories of barrels giving way in as few as 500-600 rounds of hard shooting. Of course this also pertains to hand loads too. Some people like to push the envelop on velocity. If they have a Swift or a .264 Winchester Mag. or something this hot, they want to see the Swift go through their Chrony at 4000+FPS. A steady diet of that can be abusive to a barrel and shorten its life rapidly. The .264 suffered in sales because of its reputation as a barrel burner, because factory rounds were hot. And some people liked to load their hunting loads hot.

On the other hand, some people have .220 Swifts that are 30 years old and still on the original barrel because they slack their hand loads off a bit and go for accuracy over velocity. Same with the .264 Win. Mag. and other overbore rifles.

Number four is what do you shoot? or what style do you shoot? Are you a deer hunter that goes to the range twice a year and zero's his rifle before opening day and maybe for a club shoot now and then? People like this may not shoot 30 rounds per year through a particular rifle. Then you may be a competitive shooter that shoots a couple hundred rounds a month during a particular season. Then there are varmint hunters. Some prarie dog shooters may fire 500-600 rounds over a dog town and may do it twice a week for several months while the weather is agreeable for the dogs and man to be out. So you can see some people burning a barrel out in as little as a year or so.

Number five is how many rounds do you shoot per range trip? Say you're not a competititive shooter and you don't hunt prarie dogs, and you regularly work up loads and shoot for your own satisfaction or maybe shoot in informal club shoots. How many rounds to you usually shoot at the range? I may go out one day and shoot 10 rounds checking out a load making a step change up in powder and checking accuracy. I may go out and shoot a rifle 30-50 rounds some days. So you can see this may accellerate barrel burn out time or maybe you don't shoot enough to hurt a barrel in many years.

This is why I say this question is hard to answer. There's no two people and no two guns owned by the same person going to last the same amount of rounds. It all depends on what the shooter does.

jmorris
March 12, 2011, 08:53 AM
I agree with "depends" as well as "22 LR, lifetime".

Several of my competition pistols have sent over 100,000 down range and have never had anything except bullets down the bore.

Bronze solids out of my 50 bmg and you would have to knock a few zeros off that number.

stubbicatt
March 13, 2011, 10:48 AM
I don't know brau.

I remember reading it is more a function of how many pounds of powder thru the barrel. I've heard 16 pounds is about all you will put thru a match barrel in 308, so Perhaps somewhere in that vicinity?

I had a Yugo made by Century Arms, and boy that thing could shoot. I think it had a Green Mountain barrel on it.

jerkface11
March 13, 2011, 11:00 AM
You're going to wear it out faster by cleaning it everytime than by shooting it.

gamestalker
March 13, 2011, 03:27 PM
Well 25 or so years ago I gave it some thought. But after many maximum velocity hand loads later and nothing changing, well at least in a bad way, I'm thinking barrel wear is not a concern. I have a 700 in .270win., an M77 also in .270 win., two 700s in 7mm rem. mag.. I'm reasonable as to how hot I'll run them, but their regular diet is nothing short of the highest velocity loads that can be had. I'm certain the 700 action .270 has had some where around 3K put through it. And one of my 700 7 mags has had well over 2K put through it. As I said, I used to concern myself with barrel wear, but I'm thinking these barrels are going to out live me.
I'm a stickler about keeping them clean, and probably break all the myths about what not to do when cleaning the barrels.

Redneck with a 40
March 13, 2011, 04:51 PM
I have a heavy barrel Remmy 700 SPS Tac in .308, I would expect no less than 10,000 rounds out of this rifle. I mostly shoot mid-range handload's and factory loads such as 150 grain Core-Lokt's. I'm usually 1.5 grains off the max on my handload's, I'm not trying to eek out every last fps. Also, I shoot about 500 rounds/year, so that's 20 years of shooting.

Yarddog
March 13, 2011, 05:23 PM
What about hard cast boolits ; ) Get Manny more down a barrel than FMJ,JSP & JHP JMO ; )
Y/D

papa_bear
March 13, 2011, 05:31 PM
glad to see people are actually reading the whole post before responding........:banghead:

P-32
March 13, 2011, 06:26 PM
FWIW the Highpower crowd budgets about 4,000 rounds before they figure the barrel starts to affect the 600yd scores. Maybe you can push that to 5 or even 6k. These are primarily .223 AR's. Then they use that upper for short line practice & matches.

This is my thinking and true for me.

If you enjoyed reading about "How many rounds to wear out a barrel?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!