From what I have learned from my reloading experience, you want to match the case capacity, the weight of the bullet, length of barrel with the correct corresponding powder burning rate.
In short, you want to maximize the pressure of the powder burning before or just as the bullet exits the muzzle.
A 125grn .30 round is traveling faster, and would require a faster burning powder than say a 168grn.
Bullet jump, and chamber pressures also are a factor in this, but that is a different subject.
Reading the article, looking at the differing bullets, knowing most were meant for a pistol form factor, I was left wondering if the results would be different with handloads taylored for carbine length barrels and using the corresponding powders.