I was guiding an Elk hunt yesterday and the hunter asked how to figure the sectional density of a bullet. I pulled a blank. I know it is the ratio of bullet weight in lbs. (7000 grains in a lb.) to the square of the bullet diameter in square inches. But I'll be danged if I can remember the formula or make the one I've got in my head to work.

I'd appericiate any help.

Barny

Hey barny, Good news for you. Everything you said looks to be correct to me.

Sectional Density = Bullet Weight(in pounds) divided by the Bullet Diameter Squared(in inches).

Here is an example for you using a typical Elk bullet - 225gr in a 338WinMag.

225/7000 = 0.03214 Bullet Weight in Pounds
0.338x0.338 = 0.1142 Bullet Diameter Squared

0.0321/0.1142 = 0.281 Sectional Density

Good luck to you and your Hunter.

Thanks Hotcore, I was just drawing a blank trying to get it to work for me.

Barny