22 LR Ballistics and Plotting Sheet for PRS CRPS Style shooting

It's a bit more complicated. A spinning object (bullet) creates a low pressure zone on one side and a high pressure zone on the other. The "Magnus" effect. The bullet isn't actually trying to align itself with the airflow. It is rising or falling into the zone of low air pressure (yaw). There is a lot going on with bullet trajectories. Air is not a static medium so I suspect as a bullet travels downrange it could be changing between nose up, nose down and in between depending on air pressure, velocity and direction. Theoretically, the bullet rise should stack up more over longer distances but one would need a wind of constant velocity, direction and pressure (impossible outdoors) to be able to prove or determine that. Add in the forward momentum and center of gravity of the projectile and the bullet appears that it would be skidding (trajectory not following the nose) on its way to the target.
 
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My understanding is that aerodynamic jump happens because of gyroscopic forces. If you hold a bicycle wheel and spin it, then try to change the axis, it turns at a direction that is 90 degrees to the force applied.

A helicopter swash plate works the same way.

The wind blowing from the side results in a vertical axis shift for the same reason.

However we try to explain it, it happens and to shoot well we need to compensate for it. The more accurate the rifle, the more it will matter to you.
 
Who cares??

Why make things so complicated?

I plug in my velocity into my kestrel with the custom drag curve and it’s bang on out to 450 yards…
 
dastt said:
Who cares??

Why make things so complicated?

I plug in my velocity into my kestrel with the custom drag curve and it’s bang on out to 450 yards…
Click to expand...

And without your kestrel, you are clueless. Cool, you have plenty of like minded people out there.

The chart provides a sense of scale that you will never see in the kestrel data.

The kestrel does not provide a way to keep track of your performance.

Think of the kestrel as your try data.... You then confirm the data with actual. This is a process that never ends.

The form is there so you can build a comparison between the theoretical and reality so you can develop the skills to go beyond the raw kestrel data.

You can also use the collected data to refine the parameters inside the kestrel.

But hey, if you don't want to do any of that, then don't. We probably just don't agree with what "bang on at 450" looks like from one day to the next.
 
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I have a similar attitude as Maple57. In my opinion, no ballistic calculator is "bang on" for every shot, every rifle, every cartridge, every bullet, every wind. Although if the definition of "bang on" is broad enough, it could be true.
 
Having read an article where the shooter had different lots of rimfire ammunition tested for changes in Density Altitude.
As the DA changed during a shoot, he was able to change lot numbers based on his previous tests.
It appeared this might shed some light on the SSDD Theory . . . Same Shooter Different Day . . . it really is a truth and not theory.
The answer was to get a Kestrel with DA. Either the author id not tell the whole truth or it was misinterpreted.
While my ammunition is tested and then a purchase is made, it is not tested at different DA's and four different lots are tested.
Therefore, what one rifle likes will have to do over the changes in DA.
As to plotting, my biggest concern is the location of a first shot from a clean cold barrel and the number of shots to get consistency.
My Anschutz 1710 produces better results at 100 and 200 metres than at 50 but it is probably the ammo.
The Cooper Montana produces better results at 50 and 100 but with limited testing at 200 m.
 
That is not surprising since Eley has identified 50 primary variables, 200 secondary variables and 700 tertiary variables including weather conditions during powder manufacture and the production of different Lots of Eley.
My ballistics program is corrected for DA (pressure), temperature and humidity for every range trip.
Although, I do have one particular Lot of Eley ammo that just plain shoots - no matter the conditions.
 
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I do not disagree with the previous 2 posts, but would like to add that as density altitude changes from the elevation values used to calculate the plotting sheet, elevation results will absolutely change from the plot sheet. Muzzle velocities vary according to temperature as well.

The plot sheet simply provides a base line from which you can estimate where impacts are likely to be using an estimated deviation factor.

Wind drift will not change by any meaningful amount.

If you have the energy, you could produce a range of plotting sheets tuned to different environmental conditions, but then you would have a phone book of possibilities.

The main thing is to develop the ability to estimate the offset from the plot relative to your interpretation of the weather conditions on any given day.

If you are good, the plot sheet can largely replace the kestrel. If you are not good, the plot sheet can still work in support of the kestrel.
 
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