The 6.5 mania continues

Hi tech inovations of new optics and non lead, hi balistic coeficient, 129gr bullets should also be acompanied by a ceramic lined barrel. Hopefully some such material is cabable of withstanding such a potential barrel burner.
 
I wouldn't be surprised to see it's a 338 Norma mag necked down to .264. 338 Norma is about 107gr water capacity, would probably explain the slight reduction in capacity when necked down .074".

The add said "30-06 length actions" but nothing about case diameter.

'The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.' Ecclesiastes 1:9 (King Solomon)

I'm quite content having long lasting barrels, desiring efficiency in developing velocities usually under 3000fps. I wish there was a 6.5X55, but in 7mm with capacity of powder to push 170gr bullets to 2800fps. 7mm Remington Express is the nearest to my knowledge however I expect (as in the 6.5x55) modern actions chambered for these old cases, a 7mm Mauser might be exactly what the doctor ordered. I shall call this new creation "284 NC" d:h:
 
I can push the 140 Berger to 3350 fps out of my .264 winmag with 72 gr Retumbo. FL sizing required after 3 shots though. Never tried the 130 grain but 3400 fps seems easy. What is the gain here other than an unbelted case and burning more powder? I'm still intrigued…Maybe just a little chapped that I am waiting for a new .264WM from ATRS and not a 26 Nosler lol
 
264winmag said:
I can push the 140 Berger to 3350 fps out of my .264 winmag with 72 gr Retumbo. FL sizing required after 3 shots though. Never tried the 130 grain but 3400 fps seems easy. What is the gain here other than an unbelted case and burning more powder? I'm still intrigued…Maybe just a little chapped that I am waiting for a new .264WM from ATRS and not a 26 Nosler lol
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How long is the barrel to get 3350?
 
26.75" bbl, chambered with .35" of freebore and 3.5" coal. No secret for velocity gains if desired, don't think it does much for accuracy as it's only sub moa out to 650yds comfortably. Sure smokes along though!
 
A more practical load with good brass life and decent accuracy is 67 grains @3100fps. Should go without saying that anything over that is likely unsafe in most rifles.
 
Excuse my ignorance, but is speed the reason this cartridge will prematurely wear out a barrel? If so, are there other hunting cartridges that produce similar or faster speeds? Thanks.
 
It's more the ratio of powder capacity to bore size (Expansion Ratio), which for this gun is low, much lower than the 308 for example.

This yields a high MV, but creates hysteria among those who can't afford powder, much less a new barrel for their hunting rifle every 20 years.
 
Andy said:
It's more the ratio of powder capacity to bore size (Expansion Ratio), which for this gun is low, much lower than the 308 for example.

This yields a high MV, but creates hysteria among those who can't afford powder, much less a new barrel for their hunting rifle every 20 years.[/QUOTE]

Excellent Andy, ain't that the truth!!!!!;);):D
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Bearkilr..........expansion ratio is a factor of case capacity to bore diameter, the smaller the bore in relation to the case capacity the lower the expansion ratio is for that cartridge. Think of a 257 Wby as compared to a 458 WM they are based on pretty much the same case, but the 257 must move 7" down the bore to double its chamber volume whereas the 458 only has to move roughly 2 1/4" down the bore to double it's chamber volume. This is what is known as expansion ratio. The lower the expansion ratio the longer the pressure/time curve and the longer the temp/time curve is and the longer unburnt powder is driven through the leade of the chamber. All these factors determine throat erosion, hence the lower the expansion ratio the greater the throat erosion per shot assuming equal peak pressures.
 
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