Tahnka,
Seating rifle bullets further out to "increase powder capacity" doesn't work the way you suggest, for the reason I previously stated: The faster a rifle bullet is traveling before encountering the rifling, the lower the peak pressure, because the bullet engraves more easily when traveling faster.
This has been demonstrated over and over again in pressure laboratories. You can demonstrate it yourself by shooting 5 rounds of a given load in one of your rifles, with the bullets seated out as close as possible to the lands--or even touching the lands. Next shoot 5 rounds with the same load with the bullet seated one turn of the seating-die spindle deeper, and repeat with another 5 rounds with the spindle another turn deeper. The average velocity will be slightly less with each batch of deeper-seated loads. (That is, it will be if your chronograph is accurate enough and light conditions are consistent.)
Muzzle velocity is one of the direct by-products of pressure, and the one most easily (and accurately) measured by home handloaders.
