Dead on at 100yds 4inches right at 400yds

MagTen

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Feb 17, 2012
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Got my gun shooting dead on at 100yds went to 400yds it shoots 4 inches to the right. My scope is level [checked it twice] what could be causing this.
You said dead on at 100 yards. Not enough info. Dead on to some folks could be a 4 shot group in a 2" circle. Let's say your group was 1 MOA. That is 4 MOA at 400 yards. Are your shots at 400 yards all within 4 MOA and just 5"s to right? I would make 5 shot group at 400 yards and adjust scope to where the center of that grouping was the center of your target. When you do that and go back to 100 yards I bet it will surprise you how close you are the X.
 

Lycanit

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Nov 6, 2015
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Not reading through and this may have been said. The first two targets are correct extrapolation. The 100 yard is almost 1 inch right and the 400 is right at 4 right. I'd simply say 4 clicks left barring wind.
 

Lenny Foffa

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I would try the Tall Target Test as explained by Bryan Litz in his book "Accuracy and Precision for Long Range Shooting " .( Pages 90 and 91 ). A simple test , and it will either verify or eliminate one possible cause. IMHO
 

jgs8163

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No the 100yrd target is 3 shots
Ok. What is this? I thought you stated you adjusted to zero at 100 and then shot 400. I was thinking the center shot was 1 shot at 100 to confirm and the rest at 400 are to the right?

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PNWdude67

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Ridgefield WA
No I don’t . How much will wind effect the poi at 400yds
With the Berger 215 @ 2976! A 2mph wind moves it Nearly 5” right at 400 yards so. I think you already know the answer to this and are trolling a little, but if not then, just Use your Kentucky windage and hold more “left” and send it. Good shooting:)
 

buzzyb

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Gcan

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Well my 2 cents. Without answers to my fist questions, Id suggest shooting the gun @600-1000 yrds. If the POI continues to move away, and its a gun that never did this before Id say scope mounting is off. As to anyone’s form causing this, if a person’s form is bad it is not usually consistently bad with good results. We’d be seeing flyers. If you shoot a 3/8 moa group @ 100 and 400 but the 400 group is 1moa right or left then its not form or spin drift. It doesn’t take much wind to move a group but the wind would need to be perfectly steady To shoot a good group so I‘d rule out wind.

Without shooting the gun at farther distances to prove or disprove the shift, it’s not something that can be definitively diagnosed, assuming of course your scope really is level. Before Id begin with adj mounts or moving my scope, Id shoot it farther or you may tune out a 100-400 yard problem but not remedy the cause.
if the scope truly is level, and the groups continue to be sub moa but shift is 1moa or more away per 100 yards, and If the gun or barrel is new, I’d be thinking barrel indexing. BWDIK
 

P7M13

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When I look at the targets, I see a few where you are showing some consistency, and the rest is a mess. Are you a consistent shooter?
Can you put two targets side by side at 100, shoot each 10x and have all shots be 1MOA or better? (Not this, but a different rifle?)
Making a simple assumption, the rifle is accurate.
The rest would be you.
 

emp1953

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Sep 29, 2013
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Got my gun shooting dead on at 100yds went to 400yds it shoots 4 inches to the right. My scope is level [checked it twice] what could be causing this.
What caliber rifle? What power scope? After how many shots? In addition to the information offered above regarding scope alignment is the following experience I've had. Shooting a 300 win mag I took 10 shots to get a good 100 yard zero. then I went over to the 500 yard targets only to find I couldn't hit the broad side of a barn. Came back to 100 and was dead on. A young whippersnapper who had attended Army Sniper school at Ft Benning suggested that I was getting a mirage effect from heat waves coming off the barrel. The magnums heat up a barrel a lot faster then standard calibers. High magnification exacerbates the effects of heat waves so that it looks like the shooter is trying to hit a moving target. A sheet of aluminum foil, shiny side down, slipped between the scope bell and barrel, the length of the barrel gave me a consistent 2" group at 500yds. It's always something. At one time I got paranoid if there was someone at the range watching what I was doing. Sometimes really good info can come from those casual observers. What also helped after the aluminum foil was dialing the scope back from 15x to 4x. The heat waves were no longer magnified. Also I'd put the spin drift theory to rest as well. After eliminating the possibility of a mirage effect, and after going through the scope alignment advice above, then at 400yds dope your scope "n" clicks to the left, If its dead on then, spin drift is probably contributing to your problem, and you must keep that in the back of your mind whenever you shoot at those distances.
 

emp1953

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I have always gone by the rule of thumb that to account for spin drift zero should be 1/4” left of center at 100...
It's interesting that his problem is 4" at 400yds. I wonder if it changes linearly. 5" at 500yds, 2" at 200yds etc.
 

Bart B

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Dec 25, 2005
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Got my gun shooting dead on at 100yds went to 400yds it shoots 4 inches to the right. My scope is level [checked it twice] what could be causing this.
You held the rifle different.

The barrel doesn't point to a place above point of aim equal to bullet drop plus sight height above the bore until the bullet leaves the barrel. It points somewhere else when the primer fires. During the time the bullet goes down the barrel, the bore angle at the muzzle moves. How much and what direction depends on how you hold the rifle.
 
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