bladeracer wrote:My use of the word velocity was a poor choice, energy would be more precise. If the rifle I'm using won't achieve my goal without having to run it at the ragged edge, I'll use a different rifle or cartridge that will provide the result at lower pressures. That cartridge won't be the .22-250 as it does nothing for me at all. If I'm shooting my 6.5x50mm and it's not giving me the result I want, then I'll try a 6.5x55mm, 6.5x58mm, 6.5-06, etc, and if I still can't get where I'm going with a 6.5mm bullet, then 7mmRemMag, .300WinMag and so on, until I'm happy with the result. Or, more likely well before that point, I'll re-examine the goal to see if there is simply a more-effective way of reaching it altogether, like learning to stalk a hundred meters closer to my target, or learning to read the wind better rather than rely on more velocity. I don't see any genuine reason to push any rifle into the realm of barrel-burning, unless your goal is the bragging rights of burning out a barrel in the least number of shots. I guess if you only have one rifle, and you need to get the absolute maximum out of it, then you have to weigh the damage you're doing against the result you're getting. But I see no positive value in simply trying to drastically reduce the life of your firearm. Choose something that is more realistically able to achieve your needs. Only one of my firearms (.204) is loaded even close to factory levels, but still well short of case-damaging pressures, everything else runs at significantly lower pressures. Even if I owned a barrel-burner, I'd be running it at reduced pressures anyway. The reason I asked about being able to run longer rounds is because it reduces the pressures for the same velocities. It's also why I really like using high-BC bullets, they hit harder but with lower velocities/pressures.
In these "comparison" discussions it seems to invariably come down to how much velocity a particular cartridge can achieve over others. I see it and just wonder, who cares what velocity it might be possible to push any of them. What matters to me is which one is more consistently accurate, or even more importantly, easier to build accurate loads for. I don't want a rifle like a two-stroke Grand Prix motorcycle that needs to be rebuilt and tuned for each specific circuit, on each day, for each race. I want a "four-stroke" rifle that does the job every time I take it out, regardless of the conditions, and without wearing itself out.
My dealer is a huge 6.5mm fan, so he eventually got himself a .264WinMag. It took him quite a long time to nail down an accurate load, but as soon as he'd found it, the rifle reused to maintain it. He worked out that he had put 500rds through it to find this load, and had totally destroyed the throat. It cost him two-dollars worth of barrel for each of those shots. He rebarreled it with a 7mm (I think he said 7x57mm) and sold it on. He mainly shoots long-range cartridges, .338Lap, .300WinMag, and such so I'm guessing he knows about barrel burning.
Maximum pressure is maximum pressure - regardless of bullet size/weight. Heavy bullets have higher inertia, so build pressure faster (or spike sooner) for the same burn rate - hence why slower powders are used for heavier bullets.
Longer/heavier bullets for calibre also burn barrels faster, as they have a longer dwell time that enables hot, high-pressure gases to dwell longer in the throat area.
Fact is, the more powder you need to get the job done for the same sized bullet, the more heat energy you are putting into the throat area. The most efficient cartridge is the one that reaches the same velocity for the least amount of powder. A 6.5-284 is going to burn barrels faster - even shooting at reduced loads - than a 6.5CM for the same velocity, because a 6.5-284 needs more powder to do it.
Regardless, I don't have the luxury of being able to reach for 6.5x50, 6.5x55. 6.5x58 or 6.5-06 - there is no way WAPOL would allow me to have four 6.5s on one open license! (You'd need a club or collector's license.)
Likewise, if I wanted extreme barrel life, I could have bought a 308. But I doubt a hunter would ever burn out a 6.5CM - even at the most extreme loads - shooting a few dozen rounds a year.
I bought the 6.5CM because it will shoot anything from 90-160gr and do it efficiently in a short action (stiffer, weight-saving, shorter throw etc) and with a great choice of brass, projectiles and factory ammo. It's also an inherently accurate round.
If I shoot the barrel out, well I'll just get a new one - it's still cheaper than owning four different 6.5s!
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The laws of physics do not apply to politics.