Measured Barrel Wear - how long do barrels last?

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[ARCHIVED THREAD] - Measured Barrel Wear - how long do barrels last? (Page 1 of 2)

Posted: 10/14/2005 2:50:28 PM EDT

This is a friends Douglas Chrome Moly 20" Service rifle barrel. Its life consisted of strings of:
20rds in 20 minutes offhand
20rds in 60 seconds Rapid Sitting
20rds in 70 seconds Rapid Prone
20rds in 20 minutes Slow Prone.

There are just over 5500rds through the barrel.

Here's the barrel with the TE gauge inserted. The sticker marks the depth.

Here's a brand new barrel with the TE gauge inserted. Note the location of the sticker.

Here's a the TE gauge, with the measurement rings. The ring to the far right is field reject.

At 600yds, this barrel holds 3-4MOA.
At 300yds, its is MOA.
At 200 and 100, its is still SUB MOA.

Posted: 10/14/2005 2:58:38 PM EDT

[#1]

With a bit more information, this might be very informative.

What is a TE guage, and what does it measure? What is the puropse of the USPS sticker? Why is it so far in on the older bbl, and farther out on the new one?

The point is that without abusive use, a good bbl will still group fine after 5500 rds?

Posted: 10/14/2005 3:03:59 PM EDT

[#2]

Quoted:
With a bit more information, this might be very informative.

What is a TE guage, and what does it measure? What is the puropse of the USPS sticker? Why is it so far in on the older bbl, and farther out on the new one?

The point is that without abusive use, a good bbl will still group fine after 5500 rds?

I believe he is talking about a Throat Erosion gauge.

Posted: 10/14/2005 3:06:28 PM EDT

[#3]

Yikes!!!

Posted: 10/14/2005 3:07:05 PM EDT

[#4]

Quoted:
Quoted:
With a bit more information, this might be very informative.

What is a TE guage, and what does it measure? What is the puropse of the USPS sticker? Why is it so far in on the older bbl, and farther out on the new one?

The point is that without abusive use, a good bbl will still group fine after 5500 rds?

I believe he is talking about a Throat Erosion gauge.

Alright, that makes sense then, the more throat erosion, the farther in the guage will go.

That much erosion happens after just 5000 rounds?

Posted: 10/14/2005 3:18:41 PM EDT

[#5]

What is a TE guage, and what does it measure?

>>>Throat Erosion - cartridges burn out the throat of the barrel.

What is the puropse of the USPS sticker?

>>>>Just to show how far the gauge went in since its past the marks.

Why is it so far in on the older bbl, and farther out on the new one?

>>>>>>The older barrel is more worn.

The point is that without abusive use, a good bbl will still group fine after 5500 rds?

>>>>>>Yes, at shorter ranges. I would expect this to sholot MOA at 100yds, for probably another 5000rds.

5500 is about the life span for any across the course(200, 300, 600yd) barrel, SS or chrome moly. SS barrels groups open up slowly, where chrome moly barrels seem to shoot MOA at 600 one week, and 4 MOA the next; once they get to the 5K round range.

Posted: 10/14/2005 3:35:17 PM EDT

[#6]

How much muzzle erosion does that barrel have?

Posted: 10/14/2005 4:54:40 PM EDT

[#7]

Quoted:
How much muzzle erosion does that barrel have?

Keep in mind, with a new barrel - the gauge will not go in the muzzle at ALL.

Posted: 10/14/2005 5:24:30 PM EDT

[#8]

How much velocity has she lost comapred to her sister that is new?

Posted: 10/14/2005 5:48:20 PM EDT

[#9]

I believe he is talking about a Throat Erosion gauge.

Comprehensive article about the Throat Erosion gauge here.

Interesting exerpts:

Many shooters do not realize the wear that takes place at the muzzle and how important that end is to accuracy. Here is a brief view of what happens. The gases pushing the bullet through the barrel possess a greater velocity potential than the bullet does. At the very instant the bullet breaks seal with the muzzle the gases blow past the bullet. This "blow by" effect at the time of exit tends to wash away metal at the muzzle. As the muzzle erodes, the gases start leaking around the bullet before it is really supposed to be free from the barrel. Any irregularity in the way the gases leak past the bullet will have effect on accuracy. The condition of the rifling at the muzzle and the crown have far more meaning than a few thousandths of wear at the throat.

Now some comments on throat readings from non-government barrels. For the most part, little meaning can be extracted from a throat gage reading alone. To start with, think about all the various folks out there making barrels. We know that a throat gage reading is in part determined by the bore diameter. What are the starting bore diameters for all these different barrel makers? Your guess is as good as mine.

Then consider a barrel blank of some other manufacture. Suppose the reamer used to form the chamber cuts the throat a little forward of where it is supposed to be. This brand new barrel, and a tack driver at that, may throat at a2 or 3. It could be reading at that nasty 5 on the throat gage when it has only a couple thousand rounds through it and there is a lot of "goodie" remaining - very little wear at the muzzle.

Posted: 10/14/2005 6:14:48 PM EDT

[#10]

What twist is that barrel?

Can you stick the gauge in a new chrome lined 1/7 and one w/2-3000 rounds.

This is a great post.

Posted: 10/14/2005 6:29:51 PM EDT

[#11]

WOW! That's a lot of wear.

But hey, as long as it shoots.....

Posted: 10/14/2005 6:33:57 PM EDT

[#12]

Where do I get one?

Posted: 10/14/2005 6:37:24 PM EDT

[#13]

Sounds like pretty good accuracy still for something that "guages" that poorly.

For normal people (i.e. plinkers shooting at 100yds at the local range) this barrel would definitely sound like it'd be good up to 10,000rds, like you said above.

Thanks for taking the time to post this.

WIZZO

Posted: 10/14/2005 6:53:21 PM EDT

[#14]

How much velocity has she lost comapred to her sister that is new?

We never chrony our loads. If they group, they group. Velocity doesnt matter.

I understand its not a "perfect" gauge, but it is a good reference point, for tracking TE regardless of what line it shows.

Where do I get one?

I think he got it from Frank White, when he bought his new barrel.

Posted: 10/14/2005 6:57:39 PM EDT

[#15]

Quoted:
What twist is that barrel?

Can you stick the gauge in a new chrome lined 1/7 and one w/2-3000 rounds.

This is a great post.

1:8

HP shooters will usually know the number of rounds through their barrel within 100 or so. I don know anyone who keeps track like that with a chrome lined blaster. Also, checking the Chrome Lined(any barrel actually) would only tell you something if you checked it when new, and again after 3K rounds.

Posted: 10/14/2005 7:03:04 PM EDT

[#16]

Yep, you check them new, as a reference point, then gauge the wear from there. A Bushmaster barrel may gauge differently than a Colt barrel when new, but three lines of wear is three lines of wear, regardless of the barrel. That's how it is supposed to work, IIRC.

Posted: 10/15/2005 1:28:31 PM EDT

[#17]

YUP

Posted: 10/15/2005 2:19:05 PM EDT

[#18]

Quoted:
5500 is about the life span for any across the course(200, 300, 600yd) barrel, SS or chrome moly. SS barrels groups open up slowly, where chrome moly barrels seem to shoot MOA at 600 one week, and 4 MOA the next; once they get to the 5K round range.

But all the parts-bin commandos say that no one shoots enough to wear out chrome moly barrels, and that you're a rambo wannabe if you get a chrome lined barrel!

Every week we get someone on here recommending chrome moly barrels for bugdet blaster rifles, IMHO in many cases because they got that without knowing what it was and would rather try to retroactively justify it than get another barrel better suited to putting the smackdown on the berm/water jugs/osama target.

5k-6k rounds with SS or chrome moly is fine for target shooter, but steering Joe Canplinker towards one isn't very helpful.

Ok, rant over. Good post, bigbore.

Posted: 10/15/2005 3:09:58 PM EDT

[#19]

I have an A1 upper with a used chrome lined barrel on it. It was used (ex M-16) when I got it and 12 thousand rounds later, the guage has barely moved at all.

Posted: 10/15/2005 4:26:11 PM EDT

[#20]

Quoted:
I have an A1 upper with a used chrome lined barrel on it. It was used (ex M-16) when I got it and 12 thousand rounds later, the guage has barely moved at all.

This chrome lined Colt 1:12 barrel gauged fine too. But for some reason it wouldnt group

nothings perfect.

Posted: 10/15/2005 4:37:52 PM EDT

[#21]

That is the far, far exception and not the rule.

Posted: 10/15/2005 6:15:27 PM EDT

[#22]

Quoted:
5k-6k rounds with SS or chrome moly is fine for target shooter, but steering Joe Canplinker towards one isn't very helpful.

Joe Canplinker, and most members of this board, wouldn't have even noticed that the thoat was shot out because that particular barrel still shot sub-moa at 100 yards.

Posted: 10/16/2005 1:42:05 PM EDT

[#23]

Quoted:
Quoted:
5k-6k rounds with SS or chrome moly is fine for target shooter, but steering Joe Canplinker towards one isn't very helpful.

Joe Canplinker, and most members of this board, wouldn't have even noticed that the thoat was shot out because that particular barrel still shot sub-moa at 100 yards.

Joe Canplinker, and 90% of all firearm owners in the US probably wont put 5K rounds through a single firearm in thier lifetime.

Posted: 10/16/2005 1:52:36 PM EDT

[#24]

Bigbore, or anyone:

At what point, and for what reasons would the .gov retire a bbl from a service rifle?

At what round count or point would you change the bbl in a defensive/offensive, non-competition rifle?

Posted: 10/16/2005 2:18:00 PM EDT

[#25]

Quoted:

Joe Canplinker, and 90% of all firearm owners in the US probably wont put 5K rounds through a single firearm in thier lifetime.

Yahoo!!!

I finally made the top 10% of something.

Posted: 10/16/2005 2:22:49 PM EDT

[#26]

Quoted:
Quoted:
I have an A1 upper with a used chrome lined barrel on it. It was used (ex M-16) when I got it and 12 thousand rounds later, the guage has barely moved at all.

This chrome lined Colt 1:12 barrel gauged fine too. But for some reason it wouldnt group
www.adcofirearms.com/images/rustedchrome.jpg
nothings perfect.

So much for chrome preventing rust?

Sam

Posted: 10/16/2005 2:56:55 PM EDT

[#27]

Quoted:
Quoted:
I have an A1 upper with a used chrome lined barrel on it. It was used (ex M-16) when I got it and 12 thousand rounds later, the guage has barely moved at all.

This chrome lined Colt 1:12 barrel gauged fine too. But for some reason it wouldnt group
www.adcofirearms.com/images/rustedchrome.jpg
nothings perfect.

Corrosive ammo? salt water? poor maintenance? All of the above? Was the rest of the barrel in good shape?

Posted: 10/16/2005 7:40:18 PM EDT

[#28]

Let's say an alert reader was in the market for a new 20" barrel.

Let's stipulate that he's not a Joe Canplinker that wants the cheapest barrel or a Rambo wannabe that thinks he needs a competition precision barrel.

Who would be on a short list of barrel suppliers that supply ready-to-go tubes for accurate shooting at a moderate price?

Thanks!

Posted: 10/16/2005 7:41:50 PM EDT

[#29]

I guess im in that 10% too, i have 5 ar-15s and just in 3 months of this year they each have about 1200 to 1400rounds through each of them.. i dont relaod.hey.Buy the way i dont care how long my barrel last's ..as long as my lower is in good shape ..just keep on changing barrels, it's not that expensive for a new barrel anyways.

Posted: 10/17/2005 4:10:23 PM EDT

[#30]

Quoted:
Quoted:
Quoted:
I have an A1 upper with a used chrome lined barrel on it. It was used (ex M-16) when I got it and 12 thousand rounds later, the guage has barely moved at all.

This chrome lined Colt 1:12 barrel gauged fine too. But for some reason it wouldnt group
www.adcofirearms.com/images/rustedchrome.jpg
nothings perfect.

So much for chrome preventing rust?

Sam

More like a defect in the chroming process, a rare thing.

Posted: 10/17/2005 5:22:25 PM EDT

[#31]

So no word on how much veloicty was lost on that barrel due to wear?

Posted: 10/17/2005 5:28:22 PM EDT

[#32]

Quoted:
So no word on how much veloicty was lost on that barrel due to wear?

Sorry, no.

Posted: 10/17/2005 5:40:58 PM EDT

[#33]

bigbore:
Can you answer my question posted on 10/16/2005 11:40:18 PM EDT above?

I did not mean it to be a thread hijack, and we are on the subject of barrels & wear.

Thanks

Posted: 10/17/2005 6:25:45 PM EDT

[#34]

Quoted:
Let's say an alert reader was in the market for a new 20" barrel.
Let's stipulate that he's not a Joe Canplinker that wants the cheapest barrel or a Rambo wannabe that thinks he needs a competition precision barrel.
Who would be on a short list of barrel suppliers that supply ready-to-go tubes for accurate shooting at a moderate price?
Thanks!

I'm confident any can plinker will be very happy with a standard(name brand) barrel. "Accurate" depends on many things. If all you shoot is ball ammo, a standard barrel will perform just fine. I hate defining "accurate" and I hate talking about the one good 3 shot group someone shot with "X" barrel. Too many vairables. shoot 15 10 shot groups if you wnat to learn something. The unpopular truth is a good RRA/Bushmaster/Armalite barrel will be more mechanically accurate than the shooter 99% of the time.

People put way too much time and effort into buying barrels than they should. When the shooter is good enough to tell the difference, they will know it, and wont have to ask what to buy.

And what gets me every time is when someone says "I just got X barrel and it shoots better than my old barrel did last year". No $shit, you've been practicing for a year - to think the difference is the barrel is laughable.

Posted: 10/17/2005 10:50:09 PM EDT

[#35]

Bigbore...

I'm one of those who can tell you within 100, how many rounds have gone down my barrel (at least in my Service High Power rifle). You're right, the loss of accuracy wouldn't be an issue with most shooters. Plus, the accuracy degrades slowly over time.. so it's NOT like one morning you can't shoot, lol)

I replace at around 5000 rounds, move it to a "plinker" or sell it to someone.

I use a Stoney Point OAL gauge to monitor erosion. Since I load my 600 yard ammo .010 off the lands, I know where they are, and can tell when they've eroded too far for my tastes. By the way, this is a VERY easy tool to use, and relatively cheap. If you only want to check now and then, ask someone who shoots High Power at your range if they'd measure it for you now and then.

Posted: 10/18/2005 2:52:41 AM EDT

[#36]

Quoted:
Quoted:
Quoted:
5k-6k rounds with SS or chrome moly is fine for target shooter, but steering Joe Canplinker towards one isn't very helpful.

Joe Canplinker, and most members of this board, wouldn't have even noticed that the thoat was shot out because that particular barrel still shot sub-moa at 100 yards.

Joe Canplinker, and 90% of all firearm owners in the US probably wont put 5K rounds through a single firearm in thier lifetime.

M-16 owners are the 10% for sure.

Posted: 10/18/2005 4:24:30 AM EDT

[#37]

nevermind, I hit submit before reading through whole (informative) thread...

MN

Posted: 10/18/2005 4:32:48 AM EDT

[#38]

Interesting thread.

My chrome lined blaster has approx. 4000 rounds through it. +- maybe 200 or so. I know how many cases of ammo I went through

Bigbore, you are entirely right about peoples accuracy needs.

Posted: 10/18/2005 4:18:58 PM EDT

[#39]

At what point, and for what reasons would the .gov retire a bbl from a service rifle?

When it swallows a field gauge, they try a new bolt. If that does not get headspace to an acceptable level (not close on field gauge), they swap out the barrel.

Posted: 10/18/2005 6:41:33 PM EDT

[#40]

At what point, and for what reasons would the .gov retire a bbl from a service rifle?

The usual point is when the barrel swallows the bore erosion guage to or past the reject mark.

Posted: 10/18/2005 9:25:16 PM EDT

[#41]

Quoted:

How much velocity has she lost comapred to her sister that is new?

We never chrony our loads. If they group, they group. Velocity doesnt matter.

How do you calculate bullet drop without knowing the speed of the projectile?

Posted: 10/18/2005 10:24:10 PM EDT

[#42]

Quoted:
Quoted:

Joe Canplinker, and 90% of all firearm owners in the US probably wont put 5K rounds through a single firearm in thier lifetime.

Yahoo!!!

I finally made the top 10% of something.hr

Wooo Hooo! Me too! -- And hopefully I can add my new AR to the +5k list some day too!

Posted: 10/19/2005 4:56:43 AM EDT

[#43]

Quoted:
How do you calculate bullet drop without knowing the speed of the projectile?

Knowing within a few FPS isnt going to make much difference.
from 200-300 come up 3 minutes
from 300-600 come up 12 minutes

Those come-ups will get you in the black. Weather/lighting conditions will determine within another minute what's needed to get into the X ring.

Posted: 10/19/2005 5:17:14 AM EDT

[#44]

Quoted:
Quoted:
What twist is that barrel?

Can you stick the gauge in a new chrome lined 1/7 and one w/2-3000 rounds.

This is a great post.

1:8

HP shooters will usually know the number of rounds through their barrel within 100 or so. I don know anyone who keeps track like that with a chrome lined blaster. Also, checking the Chrome Lined(any barrel actually) would only tell you something if you checked it when new, and again after 3K rounds.

I actually have four chrome lined barrels from Bushmaster and Colt with a range of 3,000 - 15,000 rounds through them. I keep a very accurate round count and would be interested in testing my barrels with a TE guage and posting the results.

Posted: 10/19/2005 6:02:24 AM EDT

[#45]

Quoted:
Quoted:
How do you calculate bullet drop without knowing the speed of the projectile?

Knowing within a few FPS isnt going to make much difference.
from 200-300 come up 3 minutes
from 300-600 come up 12 minutes

Those come-ups will get you in the black. Weather/lighting conditions will determine within another minute what's needed to get into the X ring.

That is a pretty rough way of dialing your dope. That's not to say that every round needs to be chrono'd but knowing the speed +/-75fps would take a lot of guess work out of the equation.

Posted: 10/19/2005 6:34:03 AM EDT

[#46]

Quoted:

That is a pretty rough way of dialing your dope. That's not to say that every round needs to be chrono'd but knowing the speed +/-75fps would take a lot of guess work out of the equation.

Knowing within +/-75fps is insignificant unless you are shooting at 100yds in a climate controlled tunned.

Posted: 10/19/2005 7:10:29 AM EDT

[#47]

Are you saying that an AR barrel is worthless after 5000+ rounds?

That dosen't seem liek very many rounds...to me at least.

Posted: 10/19/2005 7:32:18 AM EDT

[#48]

Quoted:
Are you saying that an AR barrel is worthless after 5000+ rounds?

That dosen't seem liek very many rounds...to me at least.

If you buy a match grade AR barrel, and want to shoot basketballs at 600yds, w/match ammo - the barrel will only do so for around 5K rounds.

If you buy a match grade AR barrel, and want to shoot eggs at 100yds w/match ammo - the barrel will do so for probably around 12-15K rounds.

Posted: 10/19/2005 7:35:53 AM EDT

[#49]

Are barrels in RRA's Entry Tactical/Elite CARs considered match grade?

Posted: 10/19/2005 7:37:48 AM EDT

[#50]

Quoted:
Are barrels in RRA's Entry Tactical/Elite CARs considered match grade?

I wouldnt consider them match barrels.

[ARCHIVED THREAD] - Measured Barrel Wear - how long do barrels last? (Page 1 of 2)

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