Plains,

The general theory behind a flat nose solid is found here: http://www.grosswildjagd.de/english1.htm

In brief, a bullet in flesh (or water) forms a vapor bubble around itself in which it travels. When the vapor bubble collapses, drag is increased and lateral forces can cause tumbling. Therefore, maintaing the vapor bubble as long as possible, and also creating a vapor bubble as large as possible, maximizes penetration.

Here is a bullet depicted in its vapor bubble:

Flat nose solids have been found to increase size and duration of the vapor bubble compared to round nose solids. They have also been observed to penetrate more deeply on game, on average, based on relatively limited field testing. Most of this evidence is anecdotal.

Another reason cited by fans of flat nose bullets is that they do a better job of maintaining straight line penetration. This is perhaps because a round nose may start to deflect off of a hard object, such as bone, before punching through, while a flat nose would tend to bite into the bone more quickly and deflect less. But I have not personally seen any difference in straight line penetration between RN and FN solids.

There is an observable difference in wound channels between FN and RN solids in my experience. Neither leave a bloodshot wound channel like a hollow point. Round noses leave a channel (and entry wound) that looks like flesh was pushed out of the way, and then the flesh collapses back on itself. This does not maximize bleeding. The FN solids punch a nice cookie cutter entrance wound, and engage in tearing of flesh that they do not even come into contact with. I have seen tearing of lungs 6 inches away from where a FN solid passed. This is a phenomena that I attribute to the larger vapor bubble created by an FN solid in flesh, which can stretch surrounding flesh beyond the limit of its elasticity, resulting in tearing of the flesh.

In sum, personally I have a strong preference for flat nose solids. The advantages I have observed are deeper penetration in flesh and larger wound channels. On elephant heads, the FN solids seem to have a slight advantage, but not as noticeable as on body shots. At this point I still reserve judgment on the straight line penetration issue.

Woodleigh solids are definitely good, but when I can get an additional foot of penetration from an FN solid, that is the one I will choose. Barnes solids seem to lag behind the Woodleigh, perhaps because Barnes uses a hemispherical RN, or perhaps because the specific gravity of a Woodleigh solid is so much higher than a Barnes solid.