Ballistic Coefficient (BC) explained

[zini 1,939]

Ballistic Coefficient (BC) explained

 

Ballistic Coefficient (BC) is essentially a measure of air drag on the pellet and the ability of the pellet to over come drag whilst in flight to its target.

 

In layman’s terms it is basically a measurement of how aerodynamic a pellet is, and how well it cuts through the air .

 

The HIGHER the number of the pellet BC the LESS drag is imparted on the pellet and the more EFFICIENT the pellet is at cutting through the air to its target whilst still RETAINING its VELOCITY and ENERGY .

 

Example

 

A FX 16 / Air Arms Field 16.0 grain pellet has a BC of 0.031 (high) .

 

Webley Mosquito Express 14.3 grain has a BC of 0.028 (medium) .

 

RWS Hobby 11.8 grain which is a flat headed pellet with lots of drag has a BC of 0.012 (low) but good for close range shooting on rats, rabbits etc due to having a large surface area and hitting hard at close range before drag or loss of velocity has any real time to affect the pellet .

 

The FX / Air Arms Fields have a better BC amount and so cut through the air better, retaining better energy at range than the Webley Mosquito Express and Hobby .

 

This said the heavier the pellet the slower it tends to travel from a sub 12 FP air rifle and so has a more parabolic shaped trajectory and quicker bullet drop .

 

This causes the shooter to have to understand hold over and hold under better and apply it more precisely than someone shooting a light weight pellet .

 

In basic terms the higher the BC is the better the pellet for long range shooting.

 

At short ranges BC doesn’t really matter much at all .

 

Heavier pellets tend to have a higher BC and therefore tend to hold their energy better at range and are not affected so much by the wind .

 

BC changes with the shape of a pellet and the speed at which the pellet is travelling. (Velocity) normally around 600 fps for a .22 calibre or 800 fps for a .177 calibre.

 

A pellet with a high BC can give you a tremendous advantage when hunting and can make the difference between a instantaneous humane kill on a animal or a animal that is hit and takes some time to die due to having less kinetic energy imparted on it at the time of impact .

 

In layman’s terms short, fat, flat nosed pellets have a lower BC than a heavy relativly long domed pellet, this said not all pellets work well in all air rifle barrels and accuracy can be made worse at greater rangers so you need to test your own barrel with different pellets to see which pellet works best for you .

 

The choices that you have are as follows:

 

Do I want a light fast pellet with a flat parabolic trajectory but will loose its energy faster at RANGE due to it having more drag to contend with, or do I want a heavier, slower pellet that has a lot more pellet drop at RANGE but retains its energy better due to having less drag?

 

I hope that this explains BC ok for everyone .

 

Here is a link to pellet weights and BC

 

http://www.photosbykev.com/wordpress/userfiles/pelletdata.htm

 

Si.

Edited May 21, 2010 by zini

[Sweeney-Todd 208]

Hiya Si.

 

Very well writen and explained mate

 

 

ATB.

 

 

 

 

Bill.

[zini 1,939]

Cheers Bill buddy.

 

Si

[venomviper 129]

hi ya si

well buddy thank you i might just be able to work it out now it baffels me matey but i will give it ago when i get back as i am just off out buddy but thanks for that i think alot of people will like this matey as not alot of us use the pc that much

 

shay

[farmerkev09 105]

thanks for that si

 

farmer

[Phantom 631]

 

Well put across bud

 

Phantom