In many ways what John (AussieGunWriter) and I do with adjusting seating depth is the same thing--except I don't seat bullets further out from the starting point.
Instead, I seat them as close to the lands as is practically possible to start with. Only rarely is this touching the lands, because I mostly load for hunting rifles, and seating a bullet into the lands is a bad idea for hunting.
Instead I start lead-core bullets around .025 inch from the lands, and monolithics .05. (Monolithics rarely shoot well when seated closer than to .05 from the lands, the reason Barnes advises starting at .05.) Then I work up loads with various powders. If the accuracy isn't what I desire, then I start seating bullets deeper until they do shoot better--or I give up on that powder/bullet combination.
The reason I only seat bullets deeper--aside from the Barnes advice, which I've found applies to every monolithic tried--is that pressure drops as bullets are seated slightly deeper, and rises when they're seated further out. (Pressure can start rising again when rifle bullets are seated a LOT deeper, but that usually occurs deeper than most of us will ever get them.)
You can observe the results of this decrease in pressure on a chronograph, as muzzle velocities normally drop a little as bullets are seated farther from the lands. Once in a while I tweak the powder charge after finding the right seating depth, to bring velocity back up, but generally the loss is too small to bother with.
Have found that far more of today's bullets will shoot better when seated farther from the lands, whether monolithics or high-BC lead-cores. There are two probable reasons for this: The hunting bullets most of us use until relatively recently were all lead-cores, with relatively blunt tangential ogives, which aren't as sensitive to seating depth.
The other possible reason was many rifles had relatively "loose" chamber throats,. These were actually standard on the military-surplus rifles so many hunters used after WWII on up through the 1960s, because loose throats could be very dirty, whether from actual dirt or the dirty-burning powders often used back then, and still allow rounds to chamber easily. These throats were enough larger in diameter that bullets could tilt somewhat on their journey to the lands if seated deeply. Thus most rifles shot best with bullets seated close to the lands.
Today, however, the throats of even many factory rifles are much smaller, often very close to bullet diameter--and of course the throats in custom chambers are often tighter yet. Thus deep-seated bullets can't tilt much, if any, before entering the rifling. So it often pays to play with deeper seating--and in fact one of my recent custom rifles, a 6.5 PRC, shoots best with most (but not all) bullets seated a full 10th of an inch (.1) from the lands.
