Dead on at 100yds 4inches right at 400yds

jimbires

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Mar 16, 2008
Messages
1,697
Location
clearfield county , Pa
I started from scratch yesterday. Made sure everything was tight to spec zeroed at 100yds. Then did the tall target test went up 12 moa shot was right on. Went to 400yds ranged with sig kilo did what it said and bingo right on. The only thing I changed was i shot off of bags instead of bipod.



you must have had bipod hop . I'm glad you're set up is good .
 

Cammo

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Oct 24, 2018
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27
Location
Australia
Read what he stated. The second target he zeroed with 1 shot at 100. The shots to the right of that are 400. Just to clarify the OP.
I did read what he posted. Second pic is the 400 yards which shows 4 MOA to the right does it not? Ill edit this. 1 MOA to the right at 400 yards as the group is approximately 4inches.
 

jgs8163

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Sep 27, 2011
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833
Location
Southern Arizona
I did read what he posted. Second pic is the 400 yards which shows 4 MOA to the right does it not? Ill edit this. 1 MOA to the right at 400 yards as the group is approximately 4inches.
Agree but his explanation was not clear. Stated “shot this group after rezero at 100”. Looks to me 1 shot made at hundred in the X and then after adjusting for 400 everything was 4” right. Not the case though after the next 3-4 pages of posts. Looks like he shot 1 shot X at 400 and after that everything way right. I’d like to know if the x at 400 is cold bore 1st shot. Anyways.... wasn’t my intention to argue. Like the 1 shot in the x at 400 though.
 

Tdeyo

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Aug 31, 2020
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119
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Montana
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...
My question would be if you are 1/4" left at 100 then how far left wouldyou be at 2,3 and 400 etc.. before spin drift takes over and at what point are you back at zero. Just playing devils advocate here in a hunting situation say where you were set up on a Bull Elk and he was in the timber on the fringes and you could see his head and had a small opening to access his vitals at 350 yds where is your bullet at in relation to being back on zero ?
 

The Oregonian

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Jul 20, 2012
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Missoula, Montana
My question would be if you are 1/4" left at 100 then how far left wouldyou be at 2,3 and 400 etc.. before spin drift takes over and at what point are you back at zero. Just playing devils advocate here in a hunting situation say where you were set up on a Bull Elk and he was in the timber on the fringes and you could see his head and had a small opening to access his vitals at 350 yds where is your bullet at in relation to being back on zero ?
I actually haven’t gotten into the quantitative side of it. I was taught that at long range school I went to.
 

buzzyb

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Oct 24, 2017
Messages
154
Agree but his explanation was not clear. Stated “shot this group after rezero at 100”. Looks to me 1 shot made at hundred in the X and then after adjusting for 400 everything was 4” right. Not the case though after the next 3-4 pages of posts. Looks like he shot 1 shot X at 400 and after that everything way right. I’d like to know if the x at 400 is cold bore 1st shot. Anyways.... wasn’t my intention to argue. Like the 1 shot in the x at 400 though.
All these shots are at 400yds.
 

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PNWdude67

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Jul 4, 2019
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128
Location
Ridgefield WA
I just came back from the range today. I zeroed two .35 Whelens, two 300wms and two 30-06es. I shot at 100, 300, 400 and 500 yards. Wind changes were: 5mph L to R, 12 mph R to L, 5 mph from rear, 14 mph from rear, 12 mph half value R to L. and a few others. Impact varied without adjusting from 100 yard windage from 6" right of target at 500 to 12-15 inches left of aimpoint at 500 yards with both of two different 300 wms. Hits at 300 yards varied from 1 inch right to 3 inches left of center when not adjusting for the wind. Rounds chronographed at 3030 ave. from a 26" barrel and 2880 from a 24" barrel. The wind drift for the -06es was greater due to lower initial velocities(around 2630fps with 180 grain Sierras). The thing to note is that there was no adjustment for windage, so impact was perfect vertically but left or right depending on wind direction and velocity. Two or three times, the wind shifted in the middle of a group. To finish up, I dialed windage in for one of my 300s and shot a 9" and a 6" steel plate at 500 yards. I did the same for a .35 and an 03A3 that's scoped with a Shepherd 3X10. Its the wind. It isn't the shooter, it isn't the rifle, it isn't the scope, it isn't scope alignment, its the wind. A 3 to 4 mph wind left to right will drift your 300's bullet 2.5 to 3.5 inches at 400 yards every time. Its the wind. I was shooting on the Ben Lomand gun club range near Calhan Colorado, from a sandbag rested position, a heavy duty wooden bench. At 400 yards, I had a 2.5 inch drift with a 5mph wind and a 4.5 inch drift with a 12mph wind using the two 300 Winchester Magnums and 180 grain Nosler BTs. Spin drift wouldn't be noticeable at 400 yards(less than an inch).
At 400 with any of the 6.5-300 magnums shooting decent BC bullets Around 3000 fps dial 1.5 mils up and hold .1 for each 2mph of full value Wind. That ends up at half a mil for a 10 mph wind. The other rule of thumb is magnums are usually 5-7 mph guns. This means for a 5 mph wind with a 5 mph gun hold .3 at 300,.4 at 400,.5 at 500 and so on .... if you have a 6 mph gun (faster and better BC bullet) it takes 6 mph wind to have the same effect.
As far as what is full value or not keep it simple. For a left to right wind coming from 730-1030 start with the full 9 o’clock value, 7 and 11 use half value 12 and 6 straight up or just shade the side its fishtailing from most. If you’re using MOA or inches you’re on your own. JK the same principles apply the number for values are just different.
 

6.5CM

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Joined
Sep 22, 2020
Messages
17
Location
Arkansas
This is what I use now to mount all of my scopes. Level up your rifle on both axis. Then check your scope mounts on both axis. Then level up your scope on both axis. Now that you have done this both your rifle and your scope are on the same axis. In other words level with each other. What did I do before this. Guessed at it.
ea154bfa-759a-4e0b-8ddf-eb76d63309f7.jpg._CB269448209_.jpg
 

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