Guys,
How many full power (3100fps) 130 gr. rounds can one reasonably expect from a 270 Win. barrel before things start to go south? This is a SS remington standard barrel.

The formula I use says with a 130 grain, and 55.5 grains of H4350, barrel life is about 1500 rounds.

Wow, that's all!

How does that formula define "barrel life"??

Spin it back a turn and rechamber....cheap solution.....

I'd like to know what criteria your formula is based on, please.

I don't know your methodology to determine that but I find it hard to believe. Please tell how you arrived at that figure. Perhaps a falling off from bench rest standards (which a .270 has never been able to achieve anyway) but for a hunting rifle, that isn't much.
If so, all those folks that are shooting grandpaw's old .270 that claim MOA groups are mistaken??? Then again, few people shoot their hunting rifles even 50 rounds a year so that would be a pretty long time. I still think it's not enough however.

Ok, if you doubt the formula, what would you say for average barrel life of a 270?

I can give a firm "I don't know" on all the above.

I did see some hard data that indicates that a 22-250 barrel will start to open up considerably after 1500 rounds. I've heard that a 30-06 will hang in for 5-8,000. I've seen people claim that their 264 Win Mag held in for over 3,000.

1500 seems low for a 270, even though it does have a lot of case capacity for its bore diameter. For that bullet, a 308 case is actually probably a better match. Ackley tested the 270-08, and only lost about 50 FPS vs. the design we have today.

Hope that helps in some small way.

I can't prove it but I don't, for 1 minute, believe it under normal use. I'm talking about letting the barrel cool down between shots. My pre-64, .270 Win was made in 1953 and still gives a boring, 1" group with 150 Partitions at 2930 fps. Dunno how many went down the tube before I bought it but...
Bear in Fairbanks

"Average" is very subjective.

For extremes, let's compare shooting those 1500 rounds in one long sitting.... hot, and no cleaning.

Then let's look at the same thing, but this time cleaning from the muzzle.

Lastly, let's shoot those 1500 rounds in slow three shot groups, carefully cleaned from the breech, with a chamber guide.

Which will have a "longer accuracy life", in the same number of rounds?

There's lots of ways to kill accuracy. Some you can recover from and regain more "life" pretty easily (a good cleaning of excess fouling), some you can't (worn crown), at least not with the help, and expense, of a gunsmith. Others are just flat out time to replace the barrel.

I have no hard data to back it up with, but would guess that with reasonable care, you should easily be able to triple or quadruple that 1500 figure, and most likely go even higher.

[bleep], most ain't gonna live enough years to bet 1500 down the tube if they let it cool betwixt shots and clean frequently.

Viva new barrels.

My pre 64 .270 purchased new in 1955 by my father and shot by yours truly since '57 has sent untold (thousands?) rounds downrange yet delivers boringly consistent inch to inch and a half groups with the load it likes.

Old friend of mine has set several benchrest world records and wouldn't give my rifle a second look.


Each to his own I say.

I think an awful lot depends upon what people consider good accuracy. If you have rifle where your really shooting consistant 0.5" groups (which is a lot different than one that every now and then puts three in a half inch) you really would notice another .2 in group size. particularly if your close to the lands and need to make adjustments to chase the lands.

On the other hand if you have a nice accurate rifle that shoots 1-1.25" and you weren't right on the lands to do it, you probably wouldn't much notice that .2" or the lands eroding away another 0.010.

The guy with the .5" group might see a big difference in X amount of rounds.. the other guy might not really notice for 3X, even though the barrels have worn the same.

It is based on the assumption that normal accurate barrel life for a .308 is 3000 rounds. The formula adjusts the 3000 up or down based on powder weight and bore area. You can find the details at this link:

Barrel Life

There is another version posted more recently for download in Excel. Have not done it, and I understand you have to unprotect it, to get it working. Link here:

Barrel Life Spreadsheet

The Bart Bobbitt method estimates .264WM barrel life at about 850 rounds. I'm on my third .264WM barrel and that number is about right. One started keyholing, and has been replaced. A second gun has group sizes at 100 yards open up from about 1 1/4" to over 3", and needs to be replaced. For shooting at moose or barn doors, it is probably still OK.

Mine was up around 4000 rounds when I started noticing groups were more like 1.25 inches instead of the usual 1 inch. 130's and 110's over 53 gr. IMR 4350, mostly. Some shot as fast as possible (ahh, youth) some shot as singles fired at groundhogs and deer.

Took about 30 years.

Dale

I would not worry about barrel life if you are going to be doing normal hunting. Like it was pointed out earlier the average hunter does not fire over 50 rounds a year. If you are going to be firing enough rounds to burn out the barrel in a short period of time, most likely you will have enough money to send the gun in to get rebarreled.

I have a 270 that has about 2500 rounds through it.

The barrel changed what it liked to shoot as the barrel got some wear on it.

I am shooting the 110g Tipped tripple shocks now in 1/2" groups with two different loads: 57g of 760 and 58g of R#17(fed215).
I shot the 58g of R#17 yesterday at 300 and groups were in the 1 1/2" range which is good to go on deer.

The load that I used to shoot when it was new was 58g of H4831 with a Win primer with a 150g Hornady flat base and 60g of H4831 with the 130g Hornady Flat base. Both of the H4831 loads are 1 1/2" at 100 now. I tried increasing the powder charge, playing with seating depth, and changing primers...all to no avail.

From shooting so many varmint rifles, I learned that Shooting 5 shot groups will shorten the barrel life as those 4th and 5th shots generate a lot of heat, if the bullets are not touching (or just about touching)in 3 shots, you are not there yet.

As long as it gives minute of deer at 200 yds, why worry...

its not like you are shooting eggs at 515 yds..or something dumb like that.

I seem to remember some gov't test that maintained "useful" accuracy into the tens of thousands.
A first hand experience I have had was with a 22-250VS that I shot matches with and took Pdog shooting. I'm not the sort to count shots but I know that rifle made 4 or 5 trips to WY where it would be shot between 800 and 1200 times. It was also shot in a monthly match where somewhere around 50-75 rounds would go down the tube. This was in addition to casual shooting and practice. When I finally sent it off to be rebarreled, it would still shoot an inch but it was a sloppy inch and, every so often, it would push one out of an inch.
This rifle was never shot so much that you couldn't pick it up by the barrel with your bare hand. Even in a Pdog field with 50 of the little beggars jumping up and down hollering "Shoot me", "Shoot me".

I have a chart I printed out long ago.....


It doesn't use bullet weight, but instead uses types of powder in relation to bore diameter. And it says the opposite of majority wisdom--slower powders burn up barrels faster.

For example in the 270 bore:

Bullsye: 75,000+ rounds
H4831: 2,250 rounds


Go figure.......



I have a 1978 vintage M700 with approximately 2500 rounds down the bore, but had it set back and rechambered at around 1500 rounds--not because the throat was burned out, but because the chamber was a bit long......probably because of all the fullhouse hunting loads I practiced with........
It still does around an inch with Noz BT's.



Casey

Casey, I had always figured that to be the case, although I had never seen anybody put it into print before.

Look at it this way: The limiting factor in a load, what ever the powder, is peak chamber pressure. And according to all known gas laws, pressure is directly equivalent to pressure.

With a slow powder like H4831, the barrel is exposed to that high temperature for many more milliseconds than it is with an extremely fast powder.

Bullet speed is more dependent upon duration of the pressure peak than it is of the peak height.

As to the OP. I have read of US Army test with the '06 where the accuracy of the barrel actually improved over the first 3000 rounds fired. Accuracy maintained to the 7000 round mark and then started to deteriorate. At 10,000 rounds the average army rifle in 30-06 shot as well as the day it left the factory.

BUT, the military '06 was a different beast than the modern 270 driving a 130 gr bullet to maximum velocity.

I have managed to wear out one rifle barrel. It is a 264 Win mag, and I spent a lot of time, bullets, and many pounds of powder trying to achieve the elusive 3200 fps with a 140 gr bullet.

It took me 2500 hundred rounds to burn up the throat on that rifle. If the copper is scrubbed out, it will still put the first three into an inch on my 132 yd target. But the next five will open up to about three or four inches. And it takes a long while with Sweet's 7.62 to get it clean again.

I would guess, as long as you keep her cool, you should get 3500 rounds or better from your 270.

I have owned a couple of very accurate .270's that would regularly group 5 shots (not just 3) into less than an inch at 100 yards. In fact one of them would put 3 shots into around 1" at 300 yards the few times I tried it.

Both started losing that kind of accuracy at around 1000 rounds, but still shot well enough to kill deer for a lot longer. So it does indeed depend on what anybody means by "shot out."