The velocity is irrelavent. You will have approximately the same amount of throat erosion from shooting 90 grain bullets at 3400 fps as you will from shooting 150 grain bullets at 2900 fps.

Erosion is caused by the temperature and DURATION of the "flame" from the powder, both of which are functions of pressure and AMOUNT of powder. A similar amount of powder (at a similar pressure) funnelled down a smaller bore (ie. .264 Win vs. .338 Win) will cause more erosion.

Bottom line: Twelve shots in ten minutes through a .270 Win at reasonable pressures will not perceptably shorten your barrel life (which has a life expectancy greater than your own life, anyway ).

One thing I've found that helps on cooling is a T-shirt to
rub down the barrel between shots after about 3 shots the
barrel is so hot on a 7mm mag I can't touch it and the weather has a lot of us shooting less in the hot months.
Carrying an extra gun is a good way to let one cool down.
I reload and shoot around 500 rounds a year through 3 different calibers ( .243,.270 and 7mm Rem Mag) and I can't
see any noticeable loss of accuracy in any of them yet. I have always heard that heat was the culprit in barrel erosion and keeping the bore clean helps lengthening
barrel life! I don't shoot full house loads in any of my
firearms accept maybe when working up a new load and most of the time I stop at the first sign of high pressure. Most
bullets will be more accurate at a speed below max I have found and the difference gained balistically speaking is only minor. If you can't hit the target, what difference
does it make how fast you shoot at it? FWIW...BLR7

You question is good, and logical! However, bore erosion is NOT CAUSED BY BULLETS!! It is caused by high-temperature gases cutting away the barrel steel just like an acetylene torch does. Because high termperature, high/pressure gases are associated with high velocity loads, it is natural to assume that the barrel damage is a product of high-velocity bullets. But it is not! The LARGER the powder charge in proportion to the bore diameter, the higher pressures will be, and the hotter the gases that go with such combinations will be also. This means the barrel will sustain more damage than cooler, lower-pressure loads produce. An example: The .264 Win. Mag. firing a 140 grain bullet at 3100 FPS MV will ruin a barrel in a lot fewer rounds than will a .270 Win. firing a 140-grain bullet at 3100 FPS!!

D.Dan,
Nope its fire and heat that erodes throats, just like a cutting torch.....As far as I know that has been pretty common knowledge for a decade or two...

Bart Bobbit's formula to calculate barrel life

I calculate that a .270 shooting 53 gr of powder should get 1457 rounds of barrel life.

Niels, you bought your rifle because you wanted the flat trajectory which will be of help in your competition.
I understand that you use the rifle mostly for hunting where a shooting sequence as in competition (i.e. more wear) will not occur.
So, shoot your 12 rounds in 10 minutes at full blast: if you'd bore scope the rifle before and after the competition, you'll not find a difference, I bet.

Interesting formula, and probably good for comparing cartridges in the same pressure class, but wouldn't a high pressure (and the resulting genreally higher temperature) cartridge have greater effect? This is not taken into account in his formula.

I used to believe that too. Maybe I'm wrong now, but I don't think so.

I'll paraphrase from Todd Kindler, I shoot a Tactical 20, so that beibg said, this is what he told me with that question: "You shouldn't worry about the erosion, life is to short, shoot it and enjoy it, that's what shooting is all about."

I hope this saying works for you as well.

I agree with the last guy, shoot it all you want and when the accuracy starts to go south, have a new tube screwed on it and shoot some more. I buy them to shoot and worries about barrel life never cross my mind. I still however don't get them hot, can't see the point in it.

HI Hot Core

I am shooting that rifle (270win), because it, so far, is the only rifle I own, that is cheap enough to feed, to shoot a lot.
My other rifles are a 93x74R double and .222rem combi. I could shoot the 222, but it is a breaktop combi. so it would be very inaccurate in a few shots.
My .270 shoots tiny groups, so I care a lot for it and I am not reluctant to spoil that accuracy by shooting hot loads right away. The .270 will shoot well with another, slower l load than the hotter one I posted, but I have had good experience with that load, because it needs less leade, a slower load will need more, as you said. Group accuracy, though, is not a major concern, since every shot is from the off hand position.
BUT
Since D.dan posted that "my load" gives me around 1400 good shots from that rifle I think that I will slow the load down and use that, untill I'll buy a 6,5 sweede for running target practise.
1400 rounds will give me less than a year of good group sizes in the .270 . Good scores with the .270 is not as important as long barrel life. I didn't buy it for practise anyway.
I bought the .270 because of its flat trajectory for hunting reddeer and scandinavian forrest birds, not for target practise. The flat trajectory doesn't matter any shooting at 100 meters running targets.
By "accient" I found that the faster bullets helped, but I'll learn to shoot a slower one. It will never mean enough to ruin the 270 in such a short time.

You are somewhat right about why the 6.5x55 is popular over here. It is partly because of its low recoil. But a lot of calibers are low recoiling, so the bggest reason is because it is so cheap to feed. 6.5x55 is supported economically by our government, which means that every sportsshooter over here can get ammo at 1/8 of the price of 3006, 270 etc. hunting ammo. I cannot reload the 270 for less than is cost me to buy new 6.5x55 ammo.
At the sportshooter ranges, over here, there are buckets of once fired 6.5x55 brass everywhere. Actually I just mailed 12 lbs of it to a fellow ARmember/US. shooter.

Answers to your ?: I can use a sling, but do not. The dist. is 100m./ 109yrds. The moose (or the deer) runs past in 4,5 sec. it runs a dist of 50 m.

Try it yourself sometime. Another way to cheap practise at running game is shooting clays thrown across the ground (rabbit clays). At much shorter dist. of course, but done with a .22 its good fun and good practise.

Thanks for the input guys. I now know what to do.

HOT CORE- Ups forgot one ? yes all shot are off hand.

Technically, neither speed or bore diameter have anything to do with bbl erosion. To get a true feeling for bbl burning potential divide the charge weight in grains by the square of the bullet diameter in inches.

Even a compressed load in a 270 is only going to yeild a factor of 821 or so, and you don't need to worry until you hit 1000. For comparison the 243 is 846, 300 Win MAG IS 881 AND 7mm MAG is 967.