
Hunter / Field Target Anything metal target related... 

Thread Tools  Display Modes 
#1




How Do You Work Out Ballistic Coefficient?
Hi,
I'm trying to get ChainGunPro (or any ballistic calculator) to estimate windage specifically for my rifle. But whilst most of the required information is straight forward the variable of Ballistic Coefficient can make a massive difference to the predictions. So how do I work it out for my rifle and pellet combination? ATB JJ
__________________
Walther LG300 Dominator Sightron III 1050x60 Air Arms TX200 Big Nikko 1050x60 HW100 
Connect With Facebook to "Like" This Thread 

#2




0.025 ,you'll not go far wrong with that

#3




Thanks Steve, but where do you get that figure from?
__________________
Walther LG300 Dominator Sightron III 1050x60 Air Arms TX200 Big Nikko 1050x60 HW100 
#4




Hi JJ
You need to measure the velocity of the pellet at two distances. Say 10 & 30 yards. Put the info into the bc calculator on chairgun  it's in the toolbox. Hope this helps Shaun 
#5




BC = (R1 – R0) / (log(V0/V1) * 8000)
Where: BC = Ballistic Coefficient R0 = Starting Range (where V0 is measured) [Yard] R1 = End Range (where V1 is measured) [Yard] V0 = Velocity at R0 [Ft/s] V1 = Velocity at R1 [Ft/s] You’ll need two chronographs. If one is measuring muzzle velocity (and is therefore close to the muzzle) then the expression becomes: BC = R / (log(MV/V1) * 8000) Where: BC = Ballistic Coefficient R = Range between the chronographs [Yard] MV = Muzzle Velocity [Ft/s] Note that the expression is extremely sensitive to the accuracy of the velocity measurements; less so to the range estimation. 8000 appears to be a rather arbitrary constant. 
#6




Excellent!
That's exactly the info I wanted. Thanks guys ATB JJ
__________________
Walther LG300 Dominator Sightron III 1050x60 Air Arms TX200 Big Nikko 1050x60 HW100 
#7




That's the BC that a much more experienced shooter than me told me years ago.
I put a 20/50 on my 8002 last night with a scope centre of 3.6".Did the clicks on chair gun,today I shot a 40 target course with plenty of reducers and only missed 1 that was a full size stander at 45yds.Cant be that far off 
#8




Did you have the wrong clicks for the stander, or did you wobble just a little bit? Fess up, now..

#9




Chairgun adjusts the BC depending on the altitude and temperature.
Since you're higher when you're taking a standing shot, the BC will be different. That'll be why he missed I reckon 
#10




Quote:
__________________
Walther LG300 Dominator Sightron III 1050x60 Air Arms TX200 Big Nikko 1050x60 HW100 
Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Ballistic coeficient  PaulD  Hunter / Field Target  8  11th September 2013 09:29 AM 
Ballistic pendulum  FirestarterUK  General Airgun Chat  5  1st June 2010 02:52 PM 