Long Range Hunting Online Magazine Coriolis effect
 Home LRH Store Forums Long Range Rifles Articles Reviews Group Hunts Shooting Classes G7 Ballistics Calculator Rules & FAQ Register Search Today's Posts Mark Forums Read

 Rifles, Bullets, Barrels & Ballistics

Coriolis effect

#22
11-09-2003, 01:41 PM
 Gold Member Join Date: Sep 2003 Location: Blighty Posts: 637
Re: Coriolis effect

Following on from Dave's premise that there could be less interesting things to do...and besides, it's now dark in my part of the world.....

I just grabbed a few figures from an artillery firing table to try to quantify the sort of effects we're talking about. The proj in question has an mv of 820m/s and a BC of around 0.3 [which surprised me until I considered how much less dense HE is than lead].

Firing at latitude of 50 degrees North, with a target at a range of 2000m (chosen so that there might be some read across to rifle shooters):

Standard stuff:
Time of flight is 2.7 sec
Drift requires a 0.5mil left correction (ie 1 metre at this range).

Rotation of the Earth stuff:
On all bearings of fire a 0.1mil left correction is required (ie 20cm at this range).
Easterly fire requires an elevation reduction equivalent to the target being 13 metres closer.
Westerly fire requires an elevation increase equivalent to the target being 13 metres further away.
(in both cases this value gradually reduces to zero as the bearing moves to due N or S.)

Bet that's surprised a few people!

There are a bunch of factors resulting from the effects caused by the Earth's rotation -Coriolis is just one of them. They interact to sometimes cancel each other, sometimes add to each other -depends on lots of things [eg consider the difference between a shot fired from zero degrees to a target at 10 degrees North (not too big a difference between Earth surface speed at both locations) versus from 80 to 90 degrees North. Factor this against Projectile Lag (time of flight and max vertex height related) and don't forget that for Westerly fire the Earth 'rises' to meet the round whereas for Easterly it 'drops away' to let the round go long]

The artillery values given are therefore the overall result of the interaction of all the effects that can be grouped as being caused by the Earth's rotation. There's little point in considering Coriolis in isolation!

I hope that's thoroughly confused everyone!
#23
11-09-2003, 01:48 PM
 Silver Member Join Date: Jul 2002 Location: France Posts: 390
Re: Coriolis effect

Dear Brown dog

have a link with Brown Dog bullet maker in CA ????????

good shooting

DAN TEC
__________________
DANTEC
#24
11-09-2003, 02:38 PM
 Silver Member Join Date: Dec 2002 Posts: 374
Re: Coriolis effect

This is BS! I just got back from the range and BOTH of my guns shot to the right! Look what you guys did to my guns now!
__________________
If you have something that you disassemble and reassemble enough times, sooner or later, you'll have two!
#25
11-09-2003, 03:24 PM
 Gold Member Join Date: Sep 2003 Location: Blighty Posts: 637
Re: Coriolis effect

Dantec,

Apologies, no link to them. I'm more-or-less due North of your location; the other side of "La Manche" -hope that won't be a problem [img]images/icons/smile.gif[/img]
#26
11-09-2003, 04:23 PM
 Platinum Member Join Date: May 2001 Posts: 2,369
Re: Coriolis effect

4mesh063

We should have listened to Darryl... All our guns are probably screwed up now. For years we shot in blissful ignorance , now were "edumacated" and can't hit anything.

Here's what I believe I'll remember best from this thread... "when I shoot bullets vertically and try to catch them in my teeth, I always run to the west." - Max
#27
03-14-2007, 11:59 PM
 Silver Member Join Date: Jun 2007 Location: Buenos Aires, ARGENTINA Posts: 131
Re: Coriolis effect

We must differentiate two distinct effects of the Coriolis acceleration ( not the force itself ) one a VERTICAL deflection which will make a shot to fall short or long in terms of range and a HORIZONTAL deflection, which will make a projectile to deviate left or right acording to the hemisphere the gun is, not the target.
__________________
regards, Gus

http://www.patagoniaballistics.com
#28
03-15-2007, 11:19 AM
 Platinum Member Join Date: Nov 2005 Location: Riggins Idaho Posts: 1,194
Re: Coriolis effect

I didn't even get through the first page of this post. Mostly dont understand. just to help you guys, you need to get out and have a life or something because you are way to smart for you'r own good.
__________________
I dont know who ever came up with the imaganary word of "Over Gunned"

 Bookmarks

 Thread Tools Display Modes Linear Mode

 Similar Threads for: Coriolis effect Thread Thread Starter Forum Replies Last Post rem Long Range Hunting & Shooting 41 05-19-2014 11:34 AM lisagrantb Long Range Hunting & Shooting 21 04-02-2011 01:22 PM jmason Rifles, Bullets, Barrels & Ballistics 15 12-13-2010 07:11 PM justgoto Long Range Hunting & Shooting 17 08-03-2010 12:37 AM Brent Rifles, Bullets, Barrels & Ballistics 2 12-26-2002 05:27 PM

All times are GMT -5. The time now is 07:36 PM.