The situation with soft point bullets as related to SD becomes more compilcated than with solids because the SD value reduces as the bullet expands. There is a very interesting article on this subject at GS Custom Bullets web site and suggests that for the hunter at least, SD is meaningless.

I can't help but think though that long for caliber bullets will kill better than than shorter ones, however I will make some concessions:

1) a heavy for caliber hunting bullet has a long bearing surface relevant to the bore of rifle barrel, and will therefore have a lower velocity at a given pressure than a shorter one.

2) a long - heavy for caliber solid bullet is more prone to failure than a shorter one.

Still - some limited experimentinig I've done with the 380/.375 Rhino seems to support my belief regarding heavy for caliber bullets. I recently compared the 380 Rhino @ 2300 fps to a 270 gr X bullet @ 2800 fps from my .375 Ultra - firing into pails of drill mud. Penatration of the two bullets was dead even, and the volume of the temporary wound cavity was very similar, however, the the permanent wound cavity was much larger for the Rhino bullet than it was for the X. Due to the high impact velocity, the petals had broken off the X bullet leaving a .63" 193 gr "solid", where as the Rhino had expanded to .92" and retained 365 grs. To my way of thinking, the larger frontal area of the expanded 380 gr. Rhino will disrupt more bone and tissue than the expanded X bullet, and allow greater blood loss with less chance of the wound closing. What would happen if the 270 gr X was slowed to the same 2300 fps and the petals had not broken off - I don't know. I do know however that a 300 gr X @ 2600 fps also lost it's petals and performed very much like the 270 gr X. The shank of the heavier X shows signs of bending however, and this may actually reduce it's effectiveness on game.