Is the reason. If hunting game up to deer sized it's not as critical, but if hunting elk sized or larger it becomes more critical.
The following is from Chuck Hawks site on SD.
"Sectional density (SD) is the numerical result of a calculation that compares a bullet's weight to its diameter. To calculate a bullet's sectional density divide the bullet's weight (in pounds) by its diameter (in inches), squared. The higher the SD number the better the SD, and the heavier a bullet is in proportion to its diameter.
SD is important because it has a significant effect on penetration. Other things being equal (like impact velocity, bullet design and material, etc.) the higher the SD number, the better the bullet's penetration. In other words, a skinny bullet of a given weight tends to penetrate better than a fat bullet of the same weight, because it concentrates the same force on a smaller area of the target. For example, if other factors are equal, a 150 grain .270 bullet will penetrate better than a 150 grain .35 caliber bullet.
Penetration is important because the bullet must get well inside an animal to disrupt the functioning of its vital organs. A bullet that fails to penetrate the fur, skin, muscle, and bone necessary to reach the vital organs is very unlikely to bring an animal down.
SD stays the same for all bullets of the same weight in the same caliber--shape does not affect SD. This information is important to remember when comparing rifle bullets."
When I determine the bullets I am going to use for elk hunting I try to get a blend of both high BC and high SD.
Thanks for finding and posting that information. It makes sense now that I read what you posted and will pay closer attention to sectional density. I have to see what it is fro the game kings I am currently using.
Slightly off-topic, but Chuck Hawks and his site contains an amazing amount of informtaion doesn't it? Just about everytime I google for rifle or bullet info I get his site and it usually has what I want to know.
I could see the small band of mule deer picking their way towards me through the sagebrush 800 plus yards away. With my 10 power binoculars I spotted a legal buck bringing up the tail. I dropped down and crouched behind a large chunk of sage just waiting for them to pass within range. Unfortunately, they stopped and began milling around before finally settling down, with a few of them laying down right out in the open. They were not going to come to me; if I wanted any closer, I'd...