COMPREHENSIVE Inter...
 

COMPREHENSIVE Internet Wide Collection of Ballistic Coefficient Data for .22 Cal Pellets  

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JungleShooter
(@jungleshooter)
Joined: 7 months ago
Posts: 26
October 2, 2018 02:43  

 

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COMPREHENSIVE  BC Table  .22cal

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Below are the introductory comments to a

comprehensive internet wide collection of ballistic coefficient data.

 

The table (1 page) and supporting evidence (50 pages) is found in a PDF document in my dropbox.

(I tried to condense the file size, but because of the photos of rebranded pellets the PDF is too large to attach in a forum post).

Link to the PDF file:

https://www.dropbox.com/s/dkf9174yr69igw4/BC%20Pellet%20Table.%20%20.22cal.%20%202018-10-02.%20%20V.125.pdf?dl=0

 

 

The heart of this 50-page article is the table on the second page – the pellet table – an overview of pellets with a relatively high ballistic coefficient (BC) (as published), with the following characteristics:

  • .22 cal (5.5mm)
  • High quality pellets (brands: JSB, H&N, RWS, Air Arms, Crosman)
  • Usually available in the US

 

Often, main pellet manufacturers rebrand pellets, selling them under a different brand and sometimes with a different pellet name. There is some discussion whether these are the same pellets or different, and I tend to think that most of them are so similar that the BC will also be very similar. (Links are included in the section Rebranded Pellets below the table.)

 

The bottom part of the table includes a rebranding list, as rebranded pellets are not mentioned separately as to make the table more complicated yet. Note that sometimes the BC was measured using a rebranded pellet, this is noted in the table with the appropriate rebranding code, e.g., RB-F.

 

The BC values found in the literature vary, sometimes in frustrating extremes. Some are reports of actual tests, often with test conditions and calculation methods reported, others are simply lists of BC data without any information where these data were taken from.

 

Each BC values has a raised number after it12, sometimes a number and a letterA7. These refer to the source list of the BC data at the beginning of the table. More details about the BC data and internet links to them are included in the section Sources of BC Data at the end of this document (which also includes brands and calibers not found in the pellet table).

 

Each entry in the source list can consist of the following:

Author (Year-Month). Test -or- List. Ballistic Calculator used, Drag model used. Muzzle Energy (aprox.). Distance of second chronograph.

Examples:

0P  H&N (2013-12). Test. 31FPE. 50y

2  ChairGun V 4.3.1. (2017). List. GA-model. Some data from the APP

4  ChronoConnect.com (2012 and Older). List

7B  ASRA (2017). Test. ChairGun Calc, GA-Model. 32FPE. 31y

Sometimes concerns about the trustworthiness of the data are mentioned.

 

 

The difference between the published BC values has to do with many factors:

  • The BC depends on the drag model used to calculate the BC. The currently best model is the GA model; many used the inferior G1 model; and the worst is a fixed drag model. The source list sometimes specifies which model was used. Also, some ballistic calculators are much more simplistic than the sophisticated, thus accurate ChairGun, cf.:

https://sites.google.com/site/scixddevexteriorballistics/

 

  • The BC depends on the atmospheric conditions. Some calculators do not even allow entering atmospheric conditions, and some shooters might not have considered recording and entering this data.

 

  • The BC depends on the velocity of the pellet (and the BC does not vary in any predictable way unless it reaches the speed of sound). The source list often specifies the muzzle energy used for the testing to give some indication how applicable the data is.

https://arxiv.org/pdf/1503.05504

Post #1 with G1 model, + Post #23 improved with GA model:

https://www.gatewaytoairguns.org/GTA/index.php?topic=14735.20

 

Bob Sterne (screen name rsterne, on the GTA forum and others), and to some extend Harry (aka Yrrah), have ventured into measuring BC data at different velocities (cf. his variable BC values for the JSB pellets in the above link). This is a very promising approach and goes beyond what this present list of published BC values accomplishes:

With a velocity-adjusted BC table, the shooter could select a BC appropriate for the muzzle velocity and intended distance to the target and use this more accurate BC for the ballistic calculations instead of a generic BC from a data base.

 

The ballistic calculator Strelok Pro (mobile app) is extremely powerful and allows the shooter to create new entries into its projectile data base. The shooter can enter various BC values for different velocities, or can enter the data for a completely new drag curve, specific for the pellet.

 

  • The BC depends on the tester’s motivation: If the tester a manufacturer who wants to promote their pellets – then they might be motivated to experiment and try to find the gun and power setting that will produce the highest BC with their particular pellet, and skew the results in their favor.

 

  • The BC depends on the tester’s carefulness: There are a lot of things that can go wrong with the ballistic chronograph and its setup, cf.:

Chronograph Accuracy Tips – 15 Practical Tips to Increase Accuracy & Reliability

 

  • A collection of things that can go wrong with determining BC can be found in the following article:

http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Programs/

 

Note also that a given pellet will produce different amounts of muzzle energy (ME) in different guns. Often, heavy pellets will produce more ME in PCP guns than in spring-powered guns, with all things being equal, cf.:

 

 

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

 

I have collected the data of this document in extensive internet searches in 2017 for my use with ballistic calculators. THANKS to all who have been so helpful by publishing BCs online.

After amassing the data I figured – Hey, this might be useful to others. I have been helped greatly through forum posts and YouTube videos, I gladly return the favor!

 

So, here it is, and without any responsibility or liability on my part for its correctness, completeness, usefulness, sanity, or vanilla flavor.

If your use of the data results in you shooting out a window, you pay for it, not me. If your use of the data results in you missing the rabbit and your dinner hops off into the sunset, I won’t pay your restaurant bill, not on that evening nor on any other. Sorry, got my own bills to pay....

 

But if you find errors, or have more BC data to add, send me an email or PM.

If and when I find the time, I’ll gladly add it and update the list in the post.

 

Happy shooting!!

Matthias


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Doug Wall
(@doug-wall)
Joined: 1 year ago
Posts: 98
October 2, 2018 06:22  

You missed the Hard Air Magazine compilation of MEASURED BC values. These were measured using a LabRadar chronograph, with the same gun, on groups of 10 pellets for each type of pellet. As you mentioned, there are several factors that affect the BC measurement. By using the same gun and testing conditions, HAM has tried to minimize as many of these as possible.

Ballistic Coefficients


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JungleShooter
(@jungleshooter)
Joined: 7 months ago
Posts: 26
October 2, 2018 09:50  

Yes, Doug, I really appreciate the HardWork of HardAir Magazine, these are the best BC data I found!
In the BC Table you’ll find them referenced in the source list under the number they deserve, Number One! (on page 16)
HardAir Magazine’s test setup is exemplary!


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Miles_M
(@miles_m)
Joined: 1 year ago
Posts: 34
October 2, 2018 13:01  

The GA drag law is of course much better for pellets, being based on pellet data, than the G1 law or a constant drag coefficient over a wide speed range. However, it should be remembered that the GA drag law is, strictly speaking, for round head diabolo pellets only. Anything else, such as pointed of flat headed pellets, will have different drag chateristics to the GA law and thus require more values of BC at the different speeds. Even for round head pellets the GA drag law cannot apply to all shapes and that is why multiple values of BC are required for the different speeds although the differences should be less than they are for other pellet types.

Since, after 50 years, the small arms industry is finally catching up with the rest of the ballistics world and producing purpose drag laws for each bullet design, it may be time for the pellet manufacturers to go the same way. Producing a drag law should be no more difficult than producing multiple BCs using modern tracking systems. The only worries I would have is that some of the velocity decay measuring devices, such as fixed head muzzle velocity radars, can give spurious results if not used with the utmost caution leading to unrealistic drag curves.

Don't believe anything you read on the internet. Assuming you can believe this of course.


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Steve in NC
(@steve-in-nc)
Dealer
Joined: 1 year ago
Posts: 296
October 2, 2018 15:39  
Posted by: Doug Wall

...HAM Ballistic Coefficients are calculated using the GA drag model...

Anyone interested in how the HAM BCs were really calculated might be interested in this post...

https://airgunwarriors.com/airgun-talk/how-does-a-hollow-point-pellet-work/#post-3479

Try it yourself.  Plug any of the HAM velocity numbers into any of the many BC calculators that embody the constant-Cd formula cited above, like this one by Pyramyd using the math described...

https://www.pyramydair.com/airgun-resources/widgets/convert.php?BCalc&u=17

...or this one by AoA...

http://www.airgunsofarizona.com/Calcs.html

...or into the formula itself...

BC = 30 / (8000 loge (MV / V30))


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JungleShooter
(@jungleshooter)
Joined: 7 months ago
Posts: 26
December 1, 2018 08:28  

Stainless Pellet. #02a

Look at that shiny hollow point! Even airgun pellets can be beautiful....  😍 

(Though, in the end, the shiny outside doesn’t much impress a squirrel, nor a bull's eye....
A pellet’s inner qualities are what truly counts when one wants to go the distance....

Wait ??? – is there a metaphor hidden somewhere about women?)


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Steve in NC
(@steve-in-nc)
Dealer
Joined: 1 year ago
Posts: 296
December 1, 2018 15:43  
Posted by: JungleShooter

Stainless Pellet. #02a

Look at that shiny hollow point! Even airgun pellets can be beautiful....  😍 

....

Wait ??? – is there a metaphor hidden somewhere about women?)

Could be.  In this case, since the CPHP's measured BC is exactly the same as the CP's, said metaphor might be, even under that thick layer of makeup, you still might find an old fashioned girl!


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