Firearm & Gun Forum - FireArmsTalk.com > Gear & Accessories > Ammunition & Reloading > bullet metric question

Reply
 
LinkBack Thread Tools Display Modes
Old 07-27-2012, 12:23 AM   #1
Feedback Score: 0 reviews
 
Join Date: Apr 2012
Posts: 28
Default bullet metric question

In my Hornady reloading manual, it lists a bullet metric labeled as "B.C." What does that measurement mean?

__________________
Pekin7 is offline  
 
Reply With Quote

Join FirearmsTalk.com Today - It's Free!

Are you a firearms enthusiast? Then we hope you will join the community. You will gain access to post, create threads, private message, upload images, join groups and more.

Firearms Talk is owned and operated by fellow firearms enthusiasts. We strive to offer a non-commercial community to learn and share information.

Join FirearmsTalk.com Today! - Click Here


Old 07-27-2012, 12:36 AM   #2
Feedback Score: 0 reviews
 
jpattersonnh's Avatar
 
Join Date: Apr 2007
Location: South central,NH
Posts: 4,960
Liked 696 Times on 477 Posts
Likes Given: 716

Default

Quote:
Originally Posted by Pekin7 View Post
In my Hornady reloading manual, it lists a bullet metric labeled as "B.C." What does that measurement mean?
Ballistic coefficient: A bullet with a high BC will travel farther than one with a low BC since it will retain more of its initial velocity as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter”
__________________

Freedom is not free. The best of us always leave too soon.

jpattersonnh is offline  
 
Reply With Quote
Old 07-27-2012, 12:42 AM   #3
Moderator
FTF_MODERATOR.png
Feedback Score: 0 reviews
 
c3shooter's Avatar
 
Join Date: Feb 2008
Location: Third bunker on the right,Central Virginia
Posts: 16,517
Liked 8643 Times on 3743 Posts
Likes Given: 1324

Default

Yp. Now in several manuals, if you go all the way to the back, and there is downrange data, broken out by BC. Gives you the retained energy and velcity per grain for different BCs starting at different speeds.

__________________

<--- Your Moderators at our weekly Troll Hunt

c3shooter is online now  
 
Reply With Quote
Old 07-27-2012, 11:27 PM   #4
Feedback Score: 0 reviews
 
Join Date: Oct 2007
Posts: 293
Liked 9 Times on 6 Posts

Default

A "metric"? Doesn't that refer to the metric measurement system; meters, centimeters, millimeters, liters, etc.?

__________________
1hole is offline  
 
Reply With Quote
Old 07-28-2012, 12:11 AM   #5
Feedback Score: 0 reviews
 
Nch22000's Avatar
 
Join Date: Apr 2012
Posts: 87
Liked 7 Times on 6 Posts

Default

Quote:
Originally Posted by 1hole
A "metric"? Doesn't that refer to the metric measurement system; meters, centimeters, millimeters, liters, etc.?
Not in this case. A "metric" is a measurement of something. Could be production, sales numbers, payroll, BC, muzzle velocity. It is just a way to compare data.
__________________
Nch22000 is offline  
 
Reply With Quote
Old 07-28-2012, 02:48 AM   #6
Feedback Score: 0 reviews
 
Join Date: Apr 2012
Location: Texas
Posts: 176
Liked 8 Times on 8 Posts

Default

Quote:
Originally Posted by Nch22000 View Post
Not in this case. A "metric" is a measurement of something. Could be production, sales numbers, payroll, BC, muzzle velocity. It is just a way to compare data.
True but I thought it's metrics, not metric.
__________________
JigSawer40 is offline  
 
Reply With Quote
Old 07-28-2012, 03:08 AM   #7
Feedback Score: 0 reviews
 
canebrake's Avatar
 
Join Date: Jan 2009
Location: 150 miles NE of Sloppy Joe's Bar
Posts: 21,941
Liked 1419 Times on 808 Posts
Likes Given: 1290

Default

FTF's List Of Acronyms
__________________
http://i695.photobucket.com/albums/v...brake02jpg.jpg

http://i1060.photobucket.com/albums/...ps18cfbeae.jpg

Get her dirty, then clean her so she starts to respect you. When her trust is complete, she will serve you well for a lifetime!

"...if doves shot back, there wouldn't be a need for a bag limit."
- orangello
canebrake is offline  
 
Reply With Quote
Old 07-28-2012, 05:37 PM   #8
Feedback Score: 0 reviews
 
oldpapps's Avatar
 
Join Date: Sep 2011
Location: Middle America,Missouri
Posts: 173
Liked 15 Times on 14 Posts
Likes Given: 13

Default

Quote:
Originally Posted by Pekin7 View Post
In my Hornady reloading manual, it lists a bullet metric labeled as "B.C." What does that measurement mean?
Back to the original intent of the question.

'B.C." is short for Ballistic Coefficient.

Think of the projectile being a tire and the air as a roadway.
A higher "B.C." would be the equivalency of a harder and or smoother road surface. A tire will role farther and easier on smooth pavement than on/in soft sand or loose gravel.

This analogy is correct only in the common effects.

With bullets, the shape of the nose and heal with the amount of mass (weight) enclosed in the air foil disruption caused by the motion of the bullet (at its present speed and that changes) are used to give the coefficient number. Closer to '1', the less loss of energy/velocity of the projectile due to the effects of the bullet's design.

Short range uses, Pistols, shot guns and the like, are effected by B.C. but the ranges are comparatively so short as to not be much of a factor.
Longer range uses and the B.C. becomes much more apparent.

I seldom get to shoot much more than a hundred yards (trees and brush), so I seldom worry with B.C.. Yes the effects are their, but I am more of a factor.

Hope this helped a little.
__________________

Enjoy,

OSOK

oldpapps is offline  
 
Reply With Quote
Old 07-28-2012, 06:14 PM   #9
Feedback Score: 0 reviews
 
Nch22000's Avatar
 
Join Date: Apr 2012
Posts: 87
Liked 7 Times on 6 Posts

Default

Quote from Wikipedia

"In ballistics, the ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight.[1] It is inversely proportional to the negative acceleration &mdash;a high number indicates a low negative acceleration. BC is a function of mass, diameter, and drag coefficient. It is given by the mass of the object divided by the diameter squared that it presents to the airflow divided by a dimensionless constant i that relates to the aerodynamics of its shape. Ballistic coefficient has units of lb/in² or kg/m². BCs for bullets are normally stated in lb/in² by their manufacturers without referring to this unit."

And also from Wikipedia

"The formula for calculating the ballistic coefficient for bullets only is as follows:[2][3]

where:
BCBullets = ballistic coefficient
SD = sectional density, SD = mass of bullet in pounds or kilograms divided by its caliber squared in inches or meters; units are lb/in2 or kg/m2.
i = form factor, i = ; (CG ~ 0.5191)
CB = Drag coefficient of the bullet
CG = Drag coefficient of the G1 model bullet
M = Mass of object, lb or kg
d = diameter of the object, in or m"

__________________
Nch22000 is offline  
 
Reply With Quote
Old 07-29-2012, 03:41 AM   #10
Feedback Score: 0 reviews
 
Join Date: Apr 2012
Posts: 28
Default Metric defined....

Here is the dictionary definition of "metric" as I used it in my question:

A metric is any type of measurement used to gauge some quantifiable component, including measurement of a company's performance, return on investment ( ROI), or any numeric comparison...

__________________
Pekin7 is offline  
 
Reply With Quote
Reply

Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Firearms Forum Replies Last Post
Lead bullet too big for RCBS .380 bullet seater The Man Ammunition & Reloading 3 10-17-2011 02:04 PM
most firearms metric or standard? warhawk77 General Rifle Discussion 5 08-30-2011 04:57 PM
357 Mag bullet question spittinfire Ammunition & Reloading 11 11-06-2009 12:33 PM
question about bullet dia. supergus Ammunition & Reloading 13 08-20-2009 02:31 AM
a question regaring bullet proof vests lowead Concealed Carrying & Personal Protection 3 07-06-2009 03:28 AM



Newest Threads