Sectional Density A bullet's weight in pounds, divided by it's squared diameter in inches.
: Well there's enough to exit an almost all shots on Moose or bear, big or small.
: I really don't understand your post's reaoning?
: A 570gr. .510" bullet, for instance has a SD of .335.
: Even a 450gr.Cast bullet has the necessary SD (approx. .270) to exit on Moose or most bears from about any angle.
: Indeed, Horold Johnson developed this round for use on the large coastal grizzlys (brown bears) found in his guiding territory in Alaska. He used 450gr. slugs and couldn't keep on inside a big bear, not matter where shot. They were cut-off .5 BMG bullets, inverted so the base was uppermost. This left a truncated cone bullet that epenetrated as a solid, but due to the cupped nose, created exceptional wound channels. From the .450 Alaskan to the .50 Alaskan, according to Harold, was a big jump in apparent and visual effectiveness.
: If there is sufficient Section Density to achieve the necessary or desired penetration, the actual # is irrevelent. This means I had a short-form easily used formula, but cannot find it.
: Or - did you mean SD as in Standard Deviation of loads. In that respect, I got SD's in the low teens with straigth black powder, SD's in the high 20's with Pyrodex which shot poorly, an SD's in the high teens with smokeless loads using H4895 and Varget.