What is sectional density in a bullet?

Sectional density (a bullet’s weight in pounds divided by its diameter squared) describes a bullet’s length for its diameter: The higher the number, the longer the bullet. Generally speaking, the larger a bullet’s sectional density, the deeper it will penetrate.

How important is sectional density of a bullet?

Stated simply, the longer your bullets in any caliber, the higher their sectional density and the better their chances for deep penetration, all else (bullet materials, construction and velocity) equal. A line-up of 30-caliber bullets from 100-grain to 165-grain clearly shows the idea behind sectional density.

What bullet has the highest sectional density?

Simply stated, if bullets of the same caliber are compared, the heaviest bullet will have the highest sectional density. It also means that if two bullets of identical weight but of different caliber are compared, the smaller caliber bullet will have the higher sectional density.

Is sectional density the same as ballistic coefficient?

In words, the Ballistic Coefficient of a bullet is it’s sectional density divided by its form factor. Sectional density is easy to calculate because it simply depends on the bullets caliber and weight. For example, the sectional density of a 175 grain .

What does SD mean gun?

SD stands for Silenced (weapon) Suggest new definition.

What does SD mean for bullets?

SD is the sectional density in (mass) pounds per square inch. the weight of the projectile is: Wlb in pounds.

Is a higher BC better?

A bullet with a high BC will travel farther than one with a low BC since it will keep its speed better, resist the wind better, and “shoot flatter” (see external ballistics). When hunting with a rifle, a higher BC is good for several reasons. A higher BC results in a flatter flight.

What does BC stand for in bullets?

In ballistics, the ballistic coefficient (BC, Cb) of a body is a measure of its ability to overcome air resistance in flight. It is inversely proportional to the negative acceleration: a high number indicates a low negative acceleration—the drag on the body is small in proportion to its mass.

What does SD mean for ammo?

Sectional density (often abbreviated SD) is the ratio of an object’s mass to its cross sectional area with respect to a given axis. It conveys how well an object’s mass is distributed (by its shape) to overcome resistance along that axis.

What is a good SD when reloading?

15 fps is considered better than average for factory produced ammunition, but still substandard for those who handload their own ammunition. 10 fps or less SD is typically the goal of most handloaders, and very few commercially available ammo suppliers are capable of producing ammo with SD’s under 10 fps.”

What is SD in ballistics?

The standard deviation is a number that describes uniformity. The smaller the number, the more uniform velocity. A standard deviation of zero means every velocity was the same. A standard deviation of 29 fps means you expect two-thirds of the individual velocities to be within 28 fps of the average.