Manufacturer listed ballistic coefficient

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Here is a BC Table — for quality pellets — in .22cal (attached below).

I have tried to assemble BC tests from all kinds of sources — and I have started just recently to run BC tests myself.


Many tests do not specify anything how they arrived at their numbers. 🤦🏻‍♂️

⁍ For example, JSB and H&N keep using the G1 drag profile — even though for many years we have the GA drag profile that was specifically made for round nose pellets.
Ballistician Miles Morris (screenname Ballisticboy) has refined the GA profile and gave us the GA₂ profile.
He also has given us a drag profile for typical airgun slugs and one for wadcutters. 👍🏼👍🏼👍🏼


⁍ Often, BC calculations are made using ballistic calculators that assume a constant drag coefficient — nothing could be further from the aerodynamic truth as drag increases greatly when approaching the speed of sound.


⁍ Because of the above mentioned large increase in drag at higher velocities (950/1000fps) it is important to publish at what velocity range the BC number was achieved. Rarely anybody reports that (thank you, HardAir Magazine for being exemplary in that).


⁍ Rarely, BC calculations take into account the atmospheric conditions — especially the air pressure — which is much lower at high altitudes — and greatly falsifies BC values.


So, here goes the BC table. The sources of the various BC numbers I have collected are referenced using a superscript number and letter. Some sources are true BC tests, others are just data collections (like ChairGun and Strelok).

Matthias



❌ BC Table .22cal

View attachment PELLETS. BC Table .22cal. [no e.m.].pdf
 
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JungleShooter said:
Here is a BC Table — for quality pellets — in .22cal (attached below).

I have tried to assemble BC tests from all kinds of sources — and I have started just recently to run BC tests myself.


Many tests do not specify anything how they arrived at their numbers. 🤦🏻‍♂️

⁍ For example, JSB and H&N keep using the G1 drag profile — even though for many years we have the GA drag profile that was specifically made for round nose pellets.
Ballistician Miles Morris (screenname Ballisticboy) has refined the GA profile and gave us the GA₂ profile.
He also has given us a drag profile for typical airgun slugs and one for wadcutters. 👍🏼👍🏼👍🏼


⁍ Often, BC calculations are made using ballistic calculators that assume a constant drag coefficient — nothing could be further from the aerodynamic truth as drag increases greatly when approaching the speed of sound.


⁍ Because of the above mentioned large increase in drag at higher velocities (950/1000fps) it is important to publish at what velocity range the BC number was achieved. Rarely anybody reports that (thank you, HardAir Magazine for being exemplary in that).


⁍ Rarely, BC calculations take into account the atmospheric conditions — especially the air pressure — which is much lower at high altitudes — and greatly falsifies BC values.


So, here goes the BC table. The sources of the various BC numbers I have collected are referenced using a superscript number and letter. Some sources are true BC tests, others are just data collections (like ChairGun and Strelok).

Matthias



❌ BC Table .22cal

View attachment 427857
Click to expand...
Do you have any other caliber pellets thanks for this one
 
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JungleShooter said:
Here is a BC Table — for quality pellets — in .22cal (attached below).

I have tried to assemble BC tests from all kinds of sources — and I have started just recently to run BC tests myself.


Many tests do not specify anything how they arrived at their numbers. 🤦🏻‍♂️

⁍ For example, JSB and H&N keep using the G1 drag profile — even though for many years we have the GA drag profile that was specifically made for round nose pellets.
Ballistician Miles Morris (screenname Ballisticboy) has refined the GA profile and gave us the GA₂ profile.
He also has given us a drag profile for typical airgun slugs and one for wadcutters. 👍🏼👍🏼👍🏼


⁍ Often, BC calculations are made using ballistic calculators that assume a constant drag coefficient — nothing could be further from the aerodynamic truth as drag increases greatly when approaching the speed of sound.


⁍ Because of the above mentioned large increase in drag at higher velocities (950/1000fps) it is important to publish at what velocity range the BC number was achieved. Rarely anybody reports that (thank you, HardAir Magazine for being exemplary in that).


⁍ Rarely, BC calculations take into account the atmospheric conditions — especially the air pressure — which is much lower at high altitudes — and greatly falsifies BC values.


So, here goes the BC table. The sources of the various BC numbers I have collected are referenced using a superscript number and letter. Some sources are true BC tests, others are just data collections (like ChairGun and Strelok).

Matthias



❌ BC Table .22cal

View attachment 427857
Click to expand...
 
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@JungleShooter

I'm glad to hear that you're going to start testing to gain some personal experience.

I anxiously await seeing your reports detailing some of the disparities between ballistic theory and ballistic reality. For example, how inconsequentially small the BC is between using G1 and GA for data based on a pellets speed at two distances. There are others, but that will likely be one of your first big eye openers.
 
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Fwiw in my testing I have observed a tendency for some guns to shoot some pellets below their listed BC. I chalk this up to instability in flight like spiraling. Some people might claim the published BCs are inflated but I think it’s just that the manufacturers are wise enough to report the BC of the pellet when it’s flying its best way, and not all guns or tunes will produce that.
 
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dgeesaman said:
Fwiw in my testing I have observed a tendency for some guns to shoot some pellets below their listed BC. I chalk this up to instability in flight like spiraling. Some people might claim the published BCs are inflated but I think it’s just that the manufacturers are wise enough to report the BC of the pellet when it’s flying its best way, and not all guns or tunes will produce that.
Click to expand...
Unfortunately, if your pellets are yawing around sufficiently to cause a significant change in BC, you will not be able to hit a barn door with it. Long before yaw angles high enough to cause the drag to change are reached, the lateral forces produced by the yaw will give huge group sizes. A yaw angle of around one degree is sufficient to cause group sizes to increase to the point the pellet would be unacceptable, but, because yaw drag is a function of yaw squared, the drag increase would be negligible at one degree.

As a minor point, spiralling appears to be caused more by increased stability rather than a loss of stability. Pellets, just like every other spin stabilized projectile, increase stability as they slow down, unless your muzzle velocities are around 1100 ft/sec.
 
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Last year the entire summer season I have tested at least 20 tins of .22 pellets from different Brands and weights between 15gn and 25gn.
I shoot many thousands into paper rings, in my gun club distances between 50 and 70 meters.
The name of the game was "elimination". Eliminating pellets what I won't be buying again, based on evidence on POI.
BC table or not, you need to shoot them.
 
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I shoot groups at distances from 10 to 35 yards every five yards and then I try to add some at 50 and 100 yards. I then play with chairgun to try and get it to match what I get from the groups. Often the bc has to change a bit. I figure the rifling of my gun may affect the bc at least a little. Maybe my guns velocity does too. I have no ability to calculate the bc and no desire to measure velocity downrange to use that in calculations. I can directly measure trajectory - poi changes with distance - so why not just do that? But having a ballistics program model for each gun tweaked to match shooting results is handy to use for distances I did not shoot at.
 
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Today I wanted to backup my Strelok data also the FX radar data I was building for couple years, just in case ;)
Both apps I organized by calibre and rifling twist rate, also how many scopes I use. So pretty much an amount of work I would like to save.
I noticed that my pellets (cal .22 and .25) use the GA Drag Function, but the slugs (.25 only) are still at G1.
Is that G1 a correct for .25 cal (mostly ZAN) slugs, weights between 37 to 44 grain, and speed in range between 900 to 950?
Somehow I missed this info along the line.

Edit: sorry forgot the most important...

37gn and 41 gn ZAN's are hollow point cup base
44gn is hollow point boatale
46gn is ball nose boatale
 
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bigHUN said:
Today I wanted to backup my Strelok data also the FX radar data I was building for couple years, just in case ;)
Both apps I organized by calibre and rifling twist rate, also how many scopes I use. So pretty much an amount of work I would like to save.
I noticed that my pellets (cal .22 and .25) use the GA Drag Function, but the slugs (.25 only) are still at G1.
Is that G1 a correct for .25 cal (mostly ZAN) slugs, weights between 37 to 44 grain, and speed in range between 900 to 950?
Somehow I missed this info along the line.

Edit: sorry forgot the most important...

37gn and 41 gn ZAN's are hollow point cup base
44gn is hollow point boatale
46gn is ball nose boatale
Click to expand...
At the speeds you are using G1 is not a good drag law to use over extended ranges. The reference drag law you should use should be the same shape as the actual drag law. The picture below shows the G1 drag law compared to a drag law for a large meplat slug, typical of the designs currently in use.

Slug G1.jpg

You can see the shapes of the drag laws are not very alike, particularly at speeds around 900-990 ft/sec. You can use the SLG0 reference drag law created specifically for airgun slugs, but you would have to input it yourself into Strelok. If you are not happy using what is an experimental drag law at this stage, the nearest alternative is RA4. The BC values you have to use will be different to those quoted based on G1.
 
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Ballisticboy said:
...You can use the SLG0 reference drag law created specifically for airgun slugs, but you would have to input it yourself into Strelok. ...
Click to expand...
Thanks. Where can I find the calculator formula for the SLGO? I cannot see a way to add it to Strelok without altering the app.
I am pretty good with math but I would ask Igor to add it to the list at next release.
 
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I don't know much about Strelok, having never used it. I did download the free version years ago, and I have read where purpose drag laws can be loaded into it. I can provide a table of Cd versus Mach number for the SLG0 drag law, or it can be obtained from the GPC ballistics software on their website. Its ultimate accuracy has still to be proved, though initial reports were favourable.
 
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Ballisticboy said:
I don't know much about Strelok, having never used it. I did download the free version years ago, and I have read where purpose drag laws can be loaded into it. I can provide a table of Cd versus Mach number for the SLG0 drag law, or it can be obtained from the GPC ballistics software on their website. Its ultimate accuracy has still to be proved, though initial reports were favourable.
Click to expand...
Thank you in advance, I would take your offer.
I am not a coder but also not afraid to try new things to mess around.
 
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