Scope Zero Offset

[fmjfirearms]

Hi Guys
I have a Switch barrel rifle, 6x47 & .284 Win.
I have zeroed the scope with the 6x47.
The .284 barrel when fitted has 2.2 mil up elevation and 1 mil right to get the rifle to Zero.
I have a Sig 2400, a Garmin 701 and Coldbore, they all I believe can put in an offset to allow for the scope turret differences.
The Sig wants it in inches or Centimetres, Garmin the same, have not even attempted Coldbore as I have only had it for a month.
The Sig app has a "Zero Height & Zero Offset"
The Garmin profile loader for the Garmin has "Zero Height & Zero Offset" and "SSF Elevation & SSF Windage"
Could somebody explain how I do it please, so I can just range the target and get a solution.
Thanks
Mark

 

[Conaso]

Zero Height. The height of the zero point at the zero range. (Typically 0.0, but in hunting applications some may use 1.0 at 100yds, as an example, to place 0 at maybe 200yds and extend point blank range.

Zero OffsetThe offset of the bullet impact to the left (negative) or right (positive) of the target center at the zero conditions.

 

[fmjfirearms]

Conaso
Thanks but I know the definitions of the terms, I was asking how to put them into a solver in mil.

 

[_Windrider_]

Conaso
Thanks but I know the definitions of the terms, I was asking how to put them into a solver in mil.

Most solvers want the actual measurement. Might have to get a ruler out on your zero target

 

[Conaso]

Not very good in writing my instructions.

I believe your Garmin and Sig apps, like Shooter, have fields for Zero Height (Elevation) and Zero Offset (Windage), whereas Strelok (mine) has Zero Offset (Vertical) amd Zero Offset (Horizontal). Same principle, just different naming conventions.

Simply, your app would have two records, one for each barrel. Once barrel would be the baseline, ZH/ZO would be zero. The other record would indicate the height and offset.

In detail...
Create a record for each "rifle," naming them slightly different, e.g., Rem700 6x47 Lapua and Rem700 .284 Win. Using the rifle wtih the 6x47 barrel, rotate the elevation and windage knobs on the 6x47 until the crosshairs (POA) and POI are both zeroed for 100yds. Once completed, adjust the "zero stop" until the knobs indicate zero - it is now the baseline. Ensure your app zero height and zero offset for the 6x47 record is set for "0.0". Whenever you use this rifle ensure the turrets are initially set for zero at the beginning of your range setting. If the scope doesn't have a zero stop then I would indicate the ZH/ZO in the app.

Next, change the barrel to the .284 Win. Go through your zeroing session, determine the elevation and windage. Let's say it is 1" high and 1/2" left. In your app, change the record for the .284 Win to reflect adjusting the scope for the new ZH and ZO. I don't know if you app is set for MOA or MILS and/or clicks, so I can't advise the settings in detail. In my app I indicate in the record where the bullet hit in clicks (optional), e.g., hitting left: 1", the app's ZO is -4 (clicks). When I have the app calculate it modifies the solution to reflect 4 clicks to the right.

DO NOT CHANGE THE SCOPE's ZERO STOP.

The turrets for the 6x47 would be set to zero for initial use, adjusted for the conditions, e.g., range, wind, temp., etc.
The turrets for the .284 would be set to the app settings reflecting the ZH/ZO. Any adjustments needed to reflect the conditions, the app would add or subtract based upon the ZH/ZO.

For each "barrel" record you should be able to allow for different bullets or loadings. I have a .223 that the rifle record reflects three different bullets, e.g., 53gr, 69gr, 77gr. , with two different powder. The 69gr and 77gr both have ZH/ZO set to zero, the 53gr is 4 clicks right (ZO) at 100yds. I don't know why, maybe barrel harmonics?

I hope I haven't just confused you even more.

 

[Deleted member 10043]

It is only useful when you use different loads from the same rifle and scope. One load is the primary zero and the others have the offset. What I don't understand is you don't have options for MILS. Switching barrels requires zeroing in again. Though I suppose the same aspect applies to different barrels same rifle as long as it is tested to be consistent. It can also be used for so called cold bore shot.

 

[Conaso]

Culpepper - never said I didn't have MILS. My app allows for MIL, MOA, SMOA, and clicks. I don't have his apps, know his scopes , his preferences, etc. Trying to generalize.

 

[fmjfirearms]

Hi Guys
Okay I have a March 5-40 x 56 MIL.MIL scope.
All my apps allow Mils.
I shoot in Mils.
I use the same rifle, a custom Build, Bighorn Action, Bartlein Barrels.
I just screw on the different barrels, a normal switch Barrel, same action, trigger, scope.
I just want to be able to have the rifle zeroed with the 6x47 barrel, turret set to "0" on windage and elevation.
The scope has Zero Stop set.
I want to be able to screw on the .284 and start shooting.
When I did this for the first time yesterday, I had to dial the elevation turret UP 2.2 mil and 1 mil Right to get the rounds zeroed.
I believe on all my apps I can put in the offsets for the .284.
I believe that you use Minus (-) for Left or Low, Positive (+) for Right & High.
All I need to do is enter the data but whatever I do does not give a result.
If the app say's I enter in cm (centimetres) do I convert the 2.2 mil & 1 mil to cm, 202 cm & 100 cm and input that?
If so do I put in +202 or -202, -100 or +100?
The manuals for these products are rubbish!
Thanks for your help
Mark

 

[TheOE800]

You need to convert the milradian value to centimeters AT your zero distance. I shot two different loads of 6.5CM with and without suppressor; had my main zero and three lower zero values entered in the app based on the measured distance FROM my main zero.

For instance, my rifle is zeroed with a 130gr load at 100 yards. Using that zero, I shoot the 140gr suppressed load at the same POA. I then measure the difference of the POI from the POA (my zero). This offset is 1mil or ~3.6 inches low, so my zero HEIGHT is -3.6in. There was no effect on windage so my zero OFFSET is 0in.

Does that help?

 

[fmjfirearms]

Hi TheOE800
Yes thanks, thats what I thought I had to do but was confused with the useless 3 different manuals I have for the different software.
I take it you think as if you are the Bullet and if you are low or left you would put in a minus and High or right a positive?
Mark

 

[TheOE800]

That’s right. Minus is for low or left, positive is for high or right.

For what it’s worth I never bothered computing the value, I shot all the loads at 100yd without adjusting turret then measured distance from POA with a ruler.

 

[fmjfirearms]

Hi
Is it correct that If I put in the offsets correctly I would expect to see on my app to say at 100m with the .284 barrel on it would say that up 2.2 mil Right 1 mil foe a zero?

 

[TheOE800]

It might help if you tell us which app you’re using, the distance your 6x47 zero is, and the distance you shot the .284 for reference.

If you do this correctly, when you calculate a firing solution for 100 yards (or whatever your zero is) for both, one will 0 adjustment and the will be 2.2mil up and 1mil to the right.

 

[fmjfirearms]

Hi
I use a Garmin 701, which you use the AB profile loader.
I also have a Sig 2400 LRF which uses an AB engine from a app on a phone to sync to the LRF.
I also use Coldbore on a Windows phone, although this is new to me
I zero all my rifles and calibres at 100 metres.
Mark

 

[fmjfirearms]

I have now spend over 4 days trying to get this to work, I think for my sanity it might be easier...but costlier to just have separate rifles!
If only I could understand what I have to put in.
I have tried +202 cm, -202 cm nothing changes in the predictions in any of the apps.
I would have expected that the .284 setup would have said that at 100m I would have to put 2.2 mil up and 1 mil right to have a zero?
But it says I dont need to put on any correction in any of the apps.
I give up!

 

[_Windrider_]

There is someone who may be able to help you, the AB team is active on this forum. @DocUSMCRetired, you have any insight?

 

[Subwrx300]

Hi
I use a Garmin 701, which you use the AB profile loader.
I also have a Sig 2400 LRF which uses an AB engine from a app on a phone to sync to the LRF.
I also use Coldbore on a Windows phone, although this is new to me
I zero all my rifles and calibres at 100 metres.
Mark

I use AB Mobile and Kestrel 5700 AB. If I do as you said (enter say "+2cm" for zero height and "-3cm" for zero offset) my zero solutions, along with all others ranges, do change by approximately the same amount.

It could be a bug in software that's preventing your entered values from being used in solution.

But... You said "+202" cm in an earlier post... was that a typo? That's a TON (2m zero shift??) which might be part of the problem.

 

[fmjfirearms]

Hi Subwrx300
You were right a typo, should have been -22 cm & -10 cm.

Can anyone tell me if when I have the .284 barrel on and I want to shoot a target at 100m which is my Zero, will the app tell me what my starting turret offset is?
I would have thought it would say I have to have 2.2 & 1 mil on to start with as thats the offset?

Thanks to everybody who is helping me sort this out.
Mark
From across the pond in the UK.

 

[Subwrx300]

Hi Subwrx300
You were right a typo, should have been -22 cm & -10 cm.

Can anyone tell me if when I have the .284 barrel on and I want to shoot a target at 100m which is my Zero, will the app tell me what my starting turret offset is?
I would have thought it would say I have to have 2.2 & 1 mil on to start with as thats the offset?

Thanks to everybody who is helping me sort this out.
Mark
From across the pond in the UK.

I just entered data similar to yours (albeit in inches and MOA solution) and have posted result below.

If UP and Right values are positive and Low/Left values are negative, a +3 height and -2 offset means impacting 3 inches high, 2 inches left of POA. My solution for 100yd shot should be ~ -3MOA (down) and +2 MOA to right.

According to AB directions on website:

I tested in Kestrel also with same result:

@DocUSMCRetired , can you explain why -2 offset (which refers to 2 inches left in my brain and according to instructions) produces the opposite solution? This should say dial RIGHT ~ 1.75 MOA not left; the solution is backwards; Pretty sure this is a bug.

Could this be related to why @fmjfirearms isn't getting his Garmin to display correct zero solution?

 

[DocUSMCRetired]

 

[Subwrx300]

View attachment 7026353

Correct except the windage solution provided by the software is INCORRECT for even zero wind. A -2 inch offset (left 2") should result in a solution that includes ~+2R (dial right ~2 MOA to hit target)...

Did you see the photos showing the reverse? Solution calls for additional Left dial when it should show Right dial. Correct?

 

[Subwrx300]

@DocUSMCRetired

Is this correct? If so, solver shows windage solution backwards. If not, please explain so that we can do it correctly.

 

[fmjfirearms]

Hi Guys
Finally got it working!
Once I ignored the instructions as I read them and looked at the target from the bullets point of view and inputted the corrections that way it worked on the Sig and Garmin, have not tried ColdBore yet.
As the .284 was Low and Left in put in Minus on the corrections and all came good.

 

[Conaso]

????

 

[Darkhorse1]

????

The 701 is definitely backwards meaning a POI of 3" high and 3" right needs to be input as negative values to get the correct data in the solver. I just got one recently, and am playing with these settings. Hopefully Garmin or AB pushes a firmware update to correct it.