Weight sorting brass

[Bart B]

While Larger magnum cases present more volume to vary(regardless of case weight), they have a much wider pressure peak(the part affected by initial containment).
Small underbore cartridges(like a 6ppc, or 30br) can work around capacity variances through sheer extreme pressure loads.
Both of which put affects to peak pressure, and barrel timing -from capacity variance, in smaller percentage.
But mid-size cartridges(like mine) can't work around capacity variances, and I believe they are affected most by it.
That's why I check it.

Questions.....

What's the point where a cartridge size changes from underbore to "atbore" (if there is such a thing) then to overbore?

What's the difference in shot hole positions vertically at longer ranges you see caused by mid-size cartridges that can't work around capacity variances? Or, what down range tests have you made to show the effect at the target and what were the results?

 

[rscott5028]

Here's one definition...

[...]Another very important thing is, the most accurate cartridge cases typically hold one grain of powder for each square millimeter of the bore's cross sectional area. Examples; .222 Rem. .22 PPC, .22BR, 6mmBR, 6mm PPC and 30 BR And in close second places to these are the 6XC and .308 Win. The 22 caliber ones do fine up to 300 yards but beyond that, it's best to use one of the 6mm's or the .308.

Any case that holds more powder is considered by many to be overbore. And these just don't shoot all that accurate...in general. Yes, there's exceptions. But the best odds desired means you'll pick one of the ones listed above. Of the three you mention, the .243 and 6mm Rem barrels will last about one third as long as the 6x47. And with the 6x47's lower recoil levels, it'll be easier to shoot accurately too.