AMLEVIN -
Howdy !
Yes... there are such things, that P.O. Ackley, Homer Powley, and others woudl call " ideal case capacity".... and "ideal bore capacity".
Ackley covers these, in his 2 volumne trestise. Reading Ackley's thoughts on thse topics would be about 16X better towards aiding your understanding... than just about anything I can say.
For most all calibre/cartridge/chamber & barrel combinatoins, a point can be reached where more powder won't equate to more velocity; even if chamber pressure remain the acceptable. What most shooters will need to need to come to girps with, is " expansion ratio " Home Powley's " Powley Computer " includes case capacity... as one key ingredient in the copmuter's " expansion ratio" predictions.
Look at it this way: for any given length/calibre barrel..... the only way to potentially increase vel would be to cut a larger chamber for a larger capacity case. But as stated before, there's upper limits to what's obtainable going this route'.
For a rifle with a given chamber size/case size and bore size... the only way to potentially increase vel would be to go with longer barrel lengths.
And again, there's limits. Not too many long distance shooters are using barrels that are say... 42" long. With the expansion ratio presented
by your cartridge/bore diam/barrel length combo's, select powders will only require a finite amount of barrel length; before diminishing returns
are encountered. Short pistol barrels... " fast powder". Long rifle barrels..... " slow(er) " burn rate powder. There's reasons why you don't run pistol powder in a rifle calibre, and vice/versa.
A thought:
Many would vote a 6PPC represents pretty much " ideal case capacity " for 6mm cal. In .30 cal, the .30BR you mentioned might get lots of votes.
As for " ideal bore capacity " ( for a 6mm rifle ), many would vote for the 6mm case/cartridge they feel gives best velocity, low "standard deviation" and " low extreme spread " numbers. This sutff makes for lively and entertaining " postings" @ accurateshooter.com.
And of course, the thoughtfull shooter will carefullly match his chosen calibre, bullet style/wt/ barrel length et al... to shooting tasks at hand.
When a .308 might be a great choice, depends on what one wants to do with it.
Well.... I'm glad I could help !?!?
With regards,
357Mag
P.S. - Get yourself into Ackley's 2 volumne work, and also high-value reading: Homer Powley's " Powley Papers"; found in the 1974 " Guns & Ammo" annual. And of course, running cartridge variable exercises on a free on-line version of Powley's computer, will work wonders to aid ones' understanding of these fascinating topics !!
