Clearly B (the GS Custom FN Solid):

a) Fairly soft copper, which is easily displaced by the rifling to begin with, regardless of drive-bands

b) Main body of bullet is not displaced at all or only slightly (depending on particular bore), only drive -bands are displaced. Those bands can be a lot less massive then in Barnes bullets as GS Custom bullets are turned (instead of pressed, as with Barnes)

c) Flat-Nose design minimizes tumbling and increases wound-cavity (both effects furthered by softness of material which causes the head to depress on impact - that also reduces breaking / bending and creates a very stable weight-forward shape in tissue).

d) Because of their reduced friction (band-design) they create a substantially shallower initial pressure curve. A steep pressure curve is every gun's enemy and created by ALL hard bullets (traditional FMJ as well as regular mono-metals, even when undersized which minimizes the problem, but does not entirely cure it).

It is the only 'solid' I load in my .470 NE up to a clocked speed of 2250 f/s ( 500 grain) (non-moly version, by the way): Recoil is not much worse then regular Federal factory FMJ at clocked 2089 f/s, while a comparison of the cases shows clearly which load produces a steeper initial curve: Factory cases - flat primer, very severe flaring of the case above the case web / GSC load - no flattened primer, flaring above case web very benign. I would load neither a Woodleigh FMJ nor a Barnes solid to those speeds (2250 f/s) in my double. Added benefit for DR owners with the GSC - does create substantially less friction, hence heat, which lessens regulation issues.