Drag data on bullet shell

[IceMan30]

I'm looking for data/info on the trajectory of spent shells/casings after firing a bullet. Drag coefficients/ factors, trajectory data, etc.

Any help is appreciated!



Keywords: bullet round shell case cartridge drag factor coefficient

 

[IRstuff]

Spent shells generally tumble, don't they?

TTFN

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[IceMan30]

I should hope so. Sorry - to be more specific, I'd like to know more about how they tumble.

Does that make more sense?

 

[IRstuff]

Not really, since that has pretty much zero to do with the drag coefficient of the bullet shell.

Is this for school?

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[IceMan30]

Again, maybe I'm not being clear. What I'd really like to know is if someone has done any research (fundamental or application-oriented) regarding the development of a drag model for spent bullet casings. For example, as they fall from aircraft-mounted guns.

The idea being, the shells fall somewhere, and has anyone tried to figure out/predict where they fall?

 

[IRstuff]

Why would there be any research on this?

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[KENAT]

Well, let me see, people get twitchy about things falling out of the sky, and casings for cannon shells are probably large/heavy/dense enough to provoke complaints, although I think some more modern aircraft capture the spent shells.

So, military training & testing ranges may have rules related to where aircraft can fire their guns and quite likely 6 DOF models to help calculate this.

Certainly this had to be done for other ballistic stores.

So certain govt establishments or their contractors may have relevant experience. In the UK Insys (formerly hunting defence, now part of LHM) used to have contracts for 6 DOF models for range safety etc.

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[IRstuff]

You treat ejecta as if they're worst case.

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[GregLocock]

Specifically the launch trajectory of missiles and bombs from aircraft into the slipstream is carefully studied, and has been for 50 years or more. Sorry, no links, you might try NACA.

I'm quite sure the infantry need to know this sort of stuff for little guns. I don't know of any reports, on the other hand I'm pretty sure I have seen a powerpoint or two on it. In that case the initial velocities would be very variable, I doubt the aerodynamics matter a great deal in comparison with that variability.

Cheers

Greg Locock


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[IRstuff]

He's looking for data on the detritus, not the actual round.

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[GregLocock]

Yes, hence my comment on infantry. Getting a red hot cartridge case down your shirt is no fun.


Cheers

Greg Locock


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[aafuni]

What is the point of your inquiry?

I would say that the driving force behind where a shell goes is how it is ejected, with aerodynamics being secondary. Rather than concerning your self with the tumbling, I would just come up with an experimental drag term to find out terminal velocity and roughly how far the wind can take the shell.

For more detailed analysis, you need to be more specific as there are many types of shells/casings, i.e. cannon rounds are a bit different from minigun rounds. Type of aircraft is also important.