While I may lack the experience of many on the forum, I have spent some considerable time building and shooting rifles in different calibers and chamberings and have reached no real conclusion as to the superiority of one case over another. I shot competitive BR with the 222, 219 Wasp, 223, 6x47, 6ppc, 6 BR, 308, and 30/40 Krag (!). The only time I felt the cartridge had much to do with the results was when there was an issue with the brass. This was the case with the 219 Wasp (a difficult forming operation and variable parent brass), the 6x47 (relatively weak brass which limited pressures), and the 6BR (case forming PITA with all sorts of resulting issues. This was before the advent of the BR Norma and Lapua BR brass. Brass was formed from 308 brass with a small primer pocket. I found forming to be much easier when I just paid Cindy Six to do it!).
Otherwise, in similar rifles, cartridges with similar capacity performed much the same and differences were more likely reflective of variations in barrels than in anything else.
I have also built and shot "F" class and fullbore rifles in various chamberings and , again, the differences are difficult to quantify. I have had similar results with the 308, the 30/40, and the 303 British. I have also shot the same barrel on the same action and chambered it in the 308 and the 30/06. I've done this twice and in one instance, the 308 seemed to shoot better while, with the other barrel, the 30/06 has the edge. I've done the same with the 260 and the 6.5x55 and, if there is an advantage in one over the other, I can't see it.
So, after forty years of building and shooting, if I am to be perfectly honest (and I try), I can only say, I don't know. GD
