How do you wear out a barrel?

[Ridge Runner]

Assuming you clean it properly and treat it right how may rounds will significantly affect a bolt action rifle?

Example: A Savage in .223? vrs a Savage in 30-06?

Does it more have to do with the bullet or the components of the barrel?

Would a .223 barrel be good for 10, 000 rounds before accuracy degrades, or would a 30-06 barrel degrade after 5000 rounds.

I would really appreciate some insight or links in regards to this.

Thank you.

[riddleofsteel]

I found this;

1. Calculate the bore area in square millimeters.

   2. Use one grain of powder for each square millimeter.  This is what
      I call the reference, or base powder charge.

      Example:  .30 caliber bore = 45.6 square millimeters.
                Base powder charge for .30 caliber is 45.6 grains.

      A .30 cal. cartridge that burns 45.6 grains of powder should give a
      barrel life of about 3000 rounds of good accuracy.

   3. If a larger cartridge is used and it burns more powder, the
      accuracy life in rounds for that bore size is reduced.  The amount
      of reduction is determined by

        a. Divide the increased charge by the base charge, then square
           the answer.

        b. Divide that answer into 3000.

      Example:  .28 caliber bore has a base charge of 38.5 grains.
                Cartridge burns 57.8 grains of powder.
                (57.8/38.5) squared is 2.25.
                3000 divided by 2.25 is 1,333 rounds.



My own experience has shown that the "over bore" cartridges like 6.5/300 Mag or 7mm STW lose the guilded edge of accuracy a lot faster than the more power to bore balanced cartridges like the 7x57, .308 or 6.5x55. It makes sense that the more powder you burn the faster the wear. Also smaller bore than burn a LOT of powder go fast.
I have seen .243's lose the edge in less than 600 rounds. Likewise 25-06 and 6.5-284's that went from sub MOA to 1.5 MOA in less than 1500 rounds. In "over bore" chamberings it is possible to actually wear out the barrel before you find the best loading. Especially if the problem is not the loading but a bedding or action problem.

Keep in mind that you do not NEED a sub MOA rifle to kill game. In an old book "The Bolt Action Rifle" Frank de Haas stated that the average commercial bolt action rifle was capable of producing groups of 3 to 4 inches at 100 yards. He went on to state that was sufficient to kill most game animals. I have no doubt he was right. Colonel Townsend Whelen  was fond of saying a gentleman was better off spending his time scouting for game than persusing tiny groups from his hunting rifle. He too, may have known something many of us forget.
Now by today's standards that 3 to 4" group is pretty grim. I doubt you could sell a rifle that gave that kind of warranty if it came wrapped in 100 dollar bills. However many old rifles on the racks today have seen their salad days of guilded accuracy go by long ago. That will not stop them from still killing a pile of game if you do your part.

[Graybeard]

Gotta disagree. You should easily be able to get over 300 really accurate rounds from even a big .300 Mag like the Weatherby or others even larger.

No reason a .30-06 or .223 shouldn't go at least 10,000 accurate rounds if not over heated. Heat is the worst enemy a barrel has. If you just keep on shooting it hot you can wear it out in a day.

Level of accuracy also matters. If you were a bench rest shooter you'd be looking for a level of accuracy that goes much faster. But a varmint hunter could take that same barrel the bench rest guy dumps and use it for several thousand more rounds with plenty of accuracy. If MOA is all you're asking a quality barrel can last far beyound 5000 rounds. Even 10,000 if treated right.

[Drue]

I use a Rem 700 Varmint in .308 for silhouette shooting. It has been used almost exclusively with a Sierra 168MK and 45gr H380. I started using it in 1981 and it has a little over 10,000 rounds through it. The extractor failed at the rivet at about 9000 ($25 to replace).  It will shoot 1-5/8" at 200M although the bullets have to be seated out pretty far now. When it gets to the point that I can't go out any farther and it won't do 2" at 200, I'll rebarrel it.

Drue

[gunnut69]

Have to agree with GB here.  A 223 can be easily destroyed in a single day of quick shooting at a dogtown or can last many thousands of rounds without loosing the sub 1 inch accuracy.  I've a 300 WinMag on an Enfield that has several thousand shots fired...  The first batch of brass wore out and the second is going fast..  Starting to split necks and had a partial head seperation..  These were all full house loads that push close to the 300 weatherby and are only safe in this rifle...  It's never required more than a click or two after a years disuse, unless the load was changed(Iswitched to the 200 grain Nosler Partition a few years back).  Shooting too quickly is the real culprit..  heat, just as GB said..  The throat will usually goes first and it moves forward as it wears...  Bullets can be seated to compensate sometimes but eventually it simply gets too long...but only after an awful lot of rounds down the tube..  You CAN destroy a barrel rather quickly with poor cleaning equipment and tecknique...

[Iowegan]

I did a lot of research on this topic. The overbore issue is real but there are more factors at work. I have to side with Graybeard on this one.

First, erosion of the throat occurs much faster when your barrel gets hot. Even a gun with typically long barrel life can be abused and worn out quickly.

Next, the shoulder angle plays a big part in how the flame is directed from the case. With popular military rounds such as a 223 Rem, 7mm Mauser, 308 Win, and 30-06, they all went through extensive testing for all sorts of conditions to include barrel / throat life. These cartridges were the best in their power range considering all the factors.

The angle of the shoulder works almost like a lens and should focus the pressure directly in line with the bore. Some cartridge's shoulder angle makes the flame-under-pressure hit the throat too much and causes flame cutting (throat erosion). A good example is the 264 Win Mag. It can suffer from excessive throat erosion in as little as 500 rounds.

Barrel life can be extended with some very simple measures. Don't shoot your gun if you can't hold your hand on the barrel without getting burnt. Clean the barrel thoroughly and properly after each shooting session. Don't shoot hot loads. Don't shoot mil-surp or foreign ammo that has mercuric primers (yes, some still do). Don't shoot tracers. Use a bore guide with your cleaning rod. Use aluminum or brass cleaning rods, never steel.

[Graybeard]

Use aluminum or brass cleaning rods, never steel.

Actually this too is very bad info.

Aluminum is the worst possible rod you can use in your rifle. Multi-piece rods are also in general not good. Brass like aluminum is too soft so abrasive particles and embed in the rod and that NOT the rod is what will wear your barrel.

So use a one piece stainless steel rod, coated or uncoated. Match the diameter of rod to bore diameter of barrel. You must have adequate clearance so rod doesn't touch bore but use as big as possible to avoid rod flex which causes it to rub the bore. With a proper size rod and jag with properly fitted patch you'll get a good snug fit in bore without it being so tight as to cause rod flex.

[Don Buckbee]

Good thread guys... :agree:
Heat=Short barrel life.
Use a good rod for cleaning.
Take care of the crown.
Don

[jvs]

Nothing wears out unless you use it.  You can buy a new pair of jeans and unless you wear them, they won't wear out.  Although I believe that jeans wear out in the washer, more than wearing them.

As far as cleaning a rifle goes, I think the proper way is to remove the bolt and go in from the breech end.  Push the rod through the bore, remove the jag and patch, attach a wet cotton swab, and pull it back.  Though you can detach the rod handle and pull it through to the muzzle.

Going in from the muzzle is basically asking for trouble.  Besides, why would you want to push all that dirt back into the action?