How do you know a rifle barrel is gone?

A

adrian44

New member
What are the telling signs that your rifle's barrel has passed its useful life and is worn out? What would happen if you keep using it afterwards? Is it just accuracy, or could there be safety issues?
 
I shot out only one barrel in my life & it was a Remington 700 factory .270 Win. As a handloader, every so often I'd re-measure & set the bullet seating depth so the bullets were just off the riflings. Over the years bullets got shallower & shallower in the case neck. Eventually I could not touch the riflings with a 130gr bullet barely seated in the neck - which was way too far out to go through the magazine. Accuracy dropped off too. When new, with the proper handload, it shot 1" or under at 100 yds. At the point I called it "shot out" it shot around 2" or a bit worse. Still perfectly useable & safe as a deer rifle. In bright light you could see the eroded throat area. I don't believe a bolt rifle can have it's barrel so shot out that it becomes dangerous.

FWIW...

...bug
 
I have a BP era Winchester Model 90. In its early life it was not cleaned propperly so the barel resembles a pitted pipe with rifling. It still is a tack driver so ther only way you can really tell is by shooting it.
 
You'll see keyholing. That's the most obvious result I can think of. If you keep shooting it, your accuracy will become erratic. I can't think of any safety issue that would result. You'd have to shoot a LOT for that to happen though.
 
I've only personally shot-out 2 barrels. In a .308 I had, the groups opened up over the course of a few hundred rounds from sub-MOA to 2" (the gun had about 6,000 rounds through it). A quick check with a throat erosion gauge confirmed the barrel was toast. In a .243 the drop off in accuracy was dramatic. In less than 40 rounds it went from being a tack driver to a scatter gun (the gun had about 1,400 rounds through it at the time).
 
IMHO, when the rifle ceases to group well.

Results from throat gages and measured wear at the muzzle always make for lively debates on firearms forums, but I have always considered the group of holes on a piece of paper at the desired distance the final test.
 
Accuracy. Eventually, yes- headspace will suffer but that takes a lot of rounds, and you would have gradual signs that's happening with the cases.

"Wearing out" a barrel really relates to throat erosion- as that will deteriorate long before the lands are worn out. The heat in the chamber throat erodes the steel and increases the formerly tight tolerances. This occurs more quickly with "hot loads" in all chamberings, but more quickly in the "barrel burners" like many magnums and some more popular chamberings like the .243.

Simply put, it's a function of how much powder is being burned in relation to the bore size. In the example above, because the .243 is a much smaller bore than the .308 with the same parent case, it will erode the barrel throat faster.

Often, with a worthwhile barrel, shooters will set back the breech, and re-chamber it to restore accuracy.
 
Read trigger643's post.
The TARGET accuracy barrel life is a lot shorter than most people think.
The better the gun and the more demanding the target, the shorter the barrel life.
Naturally it will be a lot longer if you are equipping an army and it will SEEM a lot longer if you are a once a year hunter.
 
I don't know of any safety issues with a worn barrel; in theory, the chamber could move forward due to compression of the steel, but that is going to take a whole lot more ammo, and a lot higher pressure ammo, than would be needed to wear out the barrel. If the rifle has been fired enough to cause battering of the locking lugs and lug seats, then excess headspace is a consideration, but generally, barrel wear will happen first.

The result depends a lot on what type of barrel wear. Throat erosion will allow the bullet to tilt coming out of the case mouth and the damage to its base will ruin accuracy. Muzzle wear, usually caused by cleaning from the muzzle without a muzzle protector, will also allow the bullet to tip as it exits the muzzle, and accuracy will suffer.

How bad can accuracy (or lack of it) become? As trigger643 says, a sub-MOA rifle can become a 2-4 MOA; at worst, barrel wear/damage at the muzzle can result in "bushel basket" groups.

Jim
 
I took a Savage .223 in on trade that wouldn't group standard ammo within 2". Seating bullets out worked a little better. Since the intended purpose was a deer rifle for younger Son, I started using 63-70 bullets seated out to max magazine length. It shot well enough for that purpose--1.5" +/- for several hundred shots and then I had a guy re-thread and install a Remington barrel on it(now it's a "Savington").
 
In my observations and listening to people who've rebarreled their rifles, that happens when the test group averages open up to somewhere between 50% and 100% larger.

A top ranked competitive shooter rebarrels his .308 Win. barrel that started out at 1/4 MOA accurate for the first 200 yards but opened up to 3/8 or 1/2 MOA. That happens around 3000 rounds of barrel life.

A typical big game hunter rebarrels his .308 Win. barrel that started out at 1 or 2 MOA accurate for the first 200 yards but opened up to 3 to 4 MOA. That happens around 6000 rounds of barrel life.

A military person rebarrels his 7.62 NATO barrel that started out at 3 to 4 MOA accurate for the first 200 yards but opened up to 5 to 6 MOA. That happens around 9000 rounds of barrel life.

A .300 Win Mag in the above disciplines will rebarrel at less than half those numbers.
 
When the barrel can no longer be made to shoot as accurately as you need it to shot either clean or dirty with a known accurate load.

That is different for different people with different rifles. We had an M24 sniper rifle that was over 12,000 rounds before it got sent back to Remington for a new barrel. It was just barely holding MOA for five shots for about the last 4k of that, but it did, so we kept using it until it didn't.

Jimro
 
22 caliber rimfire barrels used by top ranked smallbore competitors get replaced every 30,000 rounds or so. That happens when their 1/4 MOA accuracy at 50 yards/meters (5/8 MOA at 100) opens up about 50% or a little more.
 
Funny you asked that question. Just last week I tried to trade my Remington LVSF at a dealer. With these discontinued rifles now increasing in demand and value, I didn't even bother to run a patch through it first. Was puzzled when the young man there (who may or may not have been a trained 'smith) informed me that the bolt face and rifling near the muzzle were both worn, indicating to him a high round count and shooting through a hot barrel; he implied a "fine gun" store like their's couldn't accept in trade an obviously worn-out p.o.s. A bit insulted, especially after seeing some of the junk in the used rack, I left empty-handed, without even buying outright the hard-to-find gun I'd driven 2 hours for.
Knowing I'd only run 300 rounds from shooting groundhogs and coyotes, and sighting-in between scope changes - neither a high-speed, barrel-burning type of shooting - I dug out some old factory ammo for a "worst case" accuracy test when I got home; in a stiff breeze, I put 5 not-so-careful rounds in under 3/4 of an inch. Think I'll hang onto my "shot-out" rifle for a while.
 
It's even funnier; I actually laughed when I read:

the young man there (who may or may not have been a trained 'smith) informed me that the bolt face and rifling near the muzzle were both worn, indicating to him a high round count and shooting through a hot barrel
Click to expand...

All the smart 'smiths know that very little, if any, barrel wear happens at the muzzle of barrels cleaned from their breech end. I've known a few people shooting .308 Win. match rifles starting out with medium weight 30 inch barrels, then setting them back 1.5" every 3000 rounds four times. Each time, their barrels produced sub 1/3 MOA accuracy in 100 yard tests.

Match grade Garand barrels still shot well under 1 MOA at 600 yards after 4000 rounds through the barrel whose last 1/2 to 3/4 inch of the muzzle had no copper wash at all. And half the rounds through them are rapid fire; 10 shots in 60 second strings. It had been worn away as the bore and groove diameters opened up a few thousandths from cleaning rod rubbing; an easy sign of muzzle wear that mattered next to nothing. It was the origin of the rifling at the back end eroding away from burning powder that caused the accuracy degradation.
 
I've known a few people shooting .308 Win. match rifles starting out with medium weight 30 inch barrels, then setting them back 1.5" every 3000 rounds four times. Each time, their barrels produced sub 1/3 MOA accuracy in 100 yard tests.
Click to expand...

That's interesting. Can this be done on anything other than a barrel carrying the full diameter of the receiver at least as far forward as the set back length is contemplated? IOW...at what point is the OD of the barrel considered too small to chamber?

I know (in general terms) about setting back and re-chambering, but have never heard it done to this extent.
 
As long as the reinforce diameters around the chamber are thick enough for safety, all is well. Measure the diameters of a featherweight barrel in the chamber area then subtract the chamber diameters. Half the answer is the minimum reinforce thickness that tapers down smaller for an inch or two before the main taper to the muzzle.

The reinforce diameter at the receiver has to be larger than the tenon thread diameter.

Milder loads are best if more than one barrel setback is planned. They don't erode as much of the barrel as hotter ones.
 
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In my opinion, a barrel is shot out if accuracy degrades to an unacceptable point. Other variables might need to be eliminated, but that can be a tough go if you have to take it to a smith to get that figured out. I had a Remington 700 SPS Varmint that was always extremely finicky. Eventually it started key-holing. Took it to a smith who scoped it and shot it and gave it back and told me it was fine. Said my hand loads were too hot. Who am I to disagree with the man I just paid $100 bucks to help me? My loads were not burners. While trying to work up "milder loads" the rifle keyholed a round into the readout screen on chrony.

IMO that barrel was shot out.
 
Redneck, what loads were you shooting in that 700 the 'smith said were too hot?

How many rounds were shot in it?

I ask because I've shot several hundred proof loads (67,000 CUP / 86,000 PSI) in 7.62 NATO Garands and accuracy was as good as match ammo; no keyholing. One .30-06 Garand I tested had over 12,000 rounds through it and barely kept all shots inside 7 inches at 100 yards, but all bullet holes were round.

Extra high velocity doesn't cause keyholing. Bad bullets can keyhole at shorter ranges. That 'smith was either ignorant or crooked, in my opinion.
 
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