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spin drift & Coriolis effect

 
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  #36  
Old 03-29-2011, 07:21 PM
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Re: spin drift & Coriolis effect

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Originally Posted by Bravo 4 View Post
At least a couple times a year we shoot our .50's out to a little over 1600 meters, the same mile as your 1760 yards. As a matter of fact that's what we have scheduled this weekend.
When talking about the effects on REALLY long range shooting I believe that I have some pretty knowledgeable resources on the subject. I not only asked our Mortar Platoon SGT (a 20 year 11C), but also five 11C instructors(all MLOC grads, with close to 100 years combined experience).They all said the same thing, you cannot accurately account for Coriolis without a Mortar Ballistic Computer and input the gun's coordinates, the target's coordinates and factor in the bearing from gun to target. You cannot just say it will always land to the right. And these guys shoot out to 7200 meters. I also have a few buddies that are instructors at the Sniper School and they will say the same thing I was told going through the school, you cannot just range a target and put a number on it...you can't just favor/adjust right and call it good.
Now then, the one common factor these guys have in common is they are all Army trained. That could be the down fall of my/their experience...but I doubt it. It if was that easy I bet we would be using it.
As for the 3" right spin drift and 3" right of Coriolis at 1000 yards. I would be willing to say that it's really 6" of spin drift. Looking at the data book for our .50's shooting the MK211 rounds, it shows a .5 MOA of spin drift @ 1000 (also what I use for my .338 Edge). For our M24's most guys I know use .75-1 MOA.
look all i did was give the answer for the equation (derived from ballistics fte)for 45 degrees lat. at that lat it gets you close enouph from southern arizona to northern idaho. i listed how to quickly vector for east/west asimuth. again i did not say it was perfect but i did say close enouph. if you go closer to equator or to the north pole (notice my comment about alaska)the numbers change and will need new calcs. but for a majority of people in the us these simple numbers work. i did not mention #s for spin drift.
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  #37  
Old 03-30-2011, 09:38 AM
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Re: spin drift & Coriolis effect

Tag. I love this stuff.
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  #38  
Old 04-23-2014, 09:09 PM
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Re: spin drift & Coriolis effect

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Originally Posted by BlackSS View Post
Why don't we have LH twist barrels?
Left twist, It would only work if you are shooting northward. Shoot south and you've got it. Shoot east or west and the corialis effect changes your flight time.
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  #39  
Old 04-23-2014, 09:29 PM
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Re: spin drift & Coriolis effect

Like my wife says: "why don't you just... Become a better shot."
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  #40  
Old 04-24-2014, 01:31 AM
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Re: spin drift & Coriolis effect

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Originally Posted by Punisher View Post
Left twist, It would only work if you are shooting northward. Shoot south and you've got it. Shoot east or west and the corialis effect changes your flight time.
North or south doesn't matter. Impact WILL ALWAYS be right in the northern hemisphere.
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  #41  
Old 05-18-2014, 09:14 PM
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Re: spin drift & Coriolis effect

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Originally Posted by rem View Post
I understand your point, but lets say you account for all of the variables on your 1000 yard whitetail shot. if your gun shoots 1MOA at 1000 yards you are still very likely to miss the vital area. not to mention 1mph of wind will drift your bullet at least 4"(depending on your caliber fps and BC). I shoot at distances at targets before I ever shoot at an animal at that range. If i have 1.25 MOA worth of drift at 1000 between spin and Coriolis Effect I know exactly what it is because I have shot at that range many times before I will take the shot.
Unfortunately, if my gun only shot 1 MOA, I would not take a 1000 yard shot. I require accuracy of at leat 1/2 MOA to actually pull any shot off.
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  #42  
Old 05-19-2014, 11:34 AM
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Join Date: May 2011
Location: in the hills of vic AUS
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Re: spin drift & Coriolis effect

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Originally Posted by Punisher View Post
Unfortunately, if my gun only shot 1 MOA, I would not take a 1000 yard shot. I require accuracy of at leat 1/2 MOA to actually pull any shot off.
+1...
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