Silhouette rifle bullets?

[wonderwolf]

I was going through some websites looking for various rifle bullet designs when I kept coming across these silhouette bullets that have odd body designs and multiple grooves? and something that looks like a bit of a skirt at least in the way it tapers about halfway down the body? Does anybody care to explain some of the logic behind the general design?

Not my picture just a link to a site

http://img.photobucket.com/albums/v505/JeffinNZ/Shooting%20stuff/IMG_0110.jpg

[dk17hmr]

Im wonder if its for "breach seating" just enough there to engage the rifling. Interesting looking bullet.

[Doc Highwall]

It is a two diameter boolit. The nose section is bore riding, and the back is made to size to groove diameter plus .001-.002. The grooves on the nose portion are for lube but would have to be done by hand.