Sighting in Rifle Question

[Dom4]

Hey all I have a quick question in regards to the distance while sighting in my rifle. I have usually went to a range so this scenario has not come up for me before.

Please pardon me if this question is silly but i just cant figure out what is the proper way to do this.

The piece of land that I am going to be sighting in my new rifle on is not completely flat there is a little bit of an elevation change. If I would like a 200 yard zero would you use the line of sight range that my range finder gives me at 200 yards or would you use the angle compensated range of 200 yards to shoot at and sight it in? Thank you for all of the help in advance.

[DiabeticKripple]

Angle compensated.

The bullet will only drop over the horizontal distance.

[elkhunter11]

You use the horizontal distance to the target, as that is the distance that gravity acts on the bullet.

[Dom4]

Thank you both for the reply. I know that might have been a simple question but sighting in a rifle in this situation hasn't come up for me yet and I did not want to do it incorrectly. Thank you.

[Dom4]

Originally Posted by elkhunter11

You use the horizontal distance to the target, as that is the distance that gravity acts on the bullet.

Just to confirm you are saying to use the angle compensated distance correct?

[elkhunter11]

Originally Posted by Dom4

Just to confirm you are saying to use the angle compensated distance correct?

The actual horizontal distance, not the line of sight.

[Big Sky]

What's the angle that you measure?
or
Do you know the elevation difference between your bench and your backstop?

A little grade school math should tell you what your horizontal distance is.

C squared minus A squared equals B squared.

The horizontal measure is probably closer to the measured distance than you might think.

[elkhunter11]

The reality is, that it would take a fairly large difference in elevation, to make a noticeable difference , sighting in at 200 yards.

[Dick284]

Originally Posted by elkhunter11

The reality is, that it would take a fairly large difference in elevation, to make a noticeable difference , sighting in at 200 yards.

I agree.

You’d have to be getting into steeper than 30 degrees off of horizontal to make any difference on a 200 yd zero.

Just zero it and go.

[DiabeticKripple]

No need to measure angles etc. if you use the angle compensated setting on your rangefinder it’ll automatically do it for you.

[Jeron Kahyar]

Likely will make little to no difference at 200 yards (Ideal you would use the horizontal distance). Below is a chart for the difference between line of sight and Horizontal distance based on elevation change (at 200 yards). Just copy and past it to a .CSV file and open in excel if you want to read it easier.

P.S This file ends at 100 yards elevation change which would translate into you looking up or down at the target at a 30 degree angle. Just for a reference of how that may look at the bench.

Line of Sight (Yards),Change In elevation (Yards),Actual Horizontal Distance (Yards),Delta (Yards)
200,1,199.997,0.003
200,2,199.99,0.01
200,3,199.977,0.023
200,4,199.96,0.04
200,5,199.937,0.063
200,6,199.91,0.09
200,7,199.877,0.123
200,8,199.84,0.16
200,9,199.797,0.203
200,10,199.75,0.25
200,11,199.697,0.303
200,12,199.64,0.36
200,13,199.577,0.423
200,14,199.509,0.491
200,15,199.437,0.563
200,16,199.359,0.641
200,17,199.276,0.724
200,18,199.188,0.812
200,19,199.095,0.905
200,20,198.997,1.003
200,21,198.894,1.106
200,22,198.786,1.214
200,23,198.673,1.327
200,24,198.555,1.445
200,25,198.431,1.569
200,26,198.303,1.697
200,27,198.169,1.831
200,28,198.03,1.97
200,29,197.886,2.114
200,30,197.737,2.263
200,31,197.583,2.417
200,32,197.423,2.577
200,33,197.259,2.741
200,34,197.089,2.911
200,35,196.914,3.086
200,36,196.733,3.267
200,37,196.548,3.452
200,38,196.357,3.643
200,39,196.161,3.839
200,40,195.959,4.041
200,41,195.752,4.248
200,42,195.54,4.46
200,43,195.323,4.677
200,44,195.1,4.9
200,45,194.872,5.128
200,46,194.638,5.362
200,47,194.399,5.601
200,48,194.155,5.845
200,49,193.905,6.095
200,50,193.649,6.351
200,51,193.388,6.612
200,52,193.122,6.878
200,53,192.85,7.15
200,54,192.572,7.428
200,55,192.289,7.711
200,56,192,8
200,57,191.706,8.294
200,58,191.405,8.595
200,59,191.099,8.901
200,60,190.788,9.212
200,61,190.47,9.53
200,62,190.147,9.853
200,63,189.818,10.182
200,64,189.484,10.516
200,65,189.143,10.857
200,66,188.796,11.204
200,67,188.444,11.556
200,68,188.085,11.915
200,69,187.721,12.279
200,70,187.35,12.65
200,71,186.973,13.027
200,72,186.59,13.41
200,73,186.202,13.798
200,74,185.806,14.194
200,75,185.405,14.595
200,76,184.997,15.003
200,77,184.583,15.417
200,78,184.163,15.837
200,79,183.736,16.264
200,80,183.303,16.697
200,81,182.863,17.137
200,82,182.417,17.583
200,83,181.964,18.036
200,84,181.505,18.495
200,85,181.039,18.961
200,86,180.566,19.434
200,87,180.086,19.914
200,88,179.6,20.4
200,89,179.106,20.894
200,90,178.606,21.394
200,91,178.098,21.902
200,92,177.584,22.416
200,93,177.062,22.938
200,94,176.533,23.467
200,95,175.997,24.003
200,96,175.454,24.546
200,97,174.903,25.097
200,98,174.344,25.656
200,99,173.779,26.221
200,100,173.205,26.795

[Ackleyman]

Originally Posted by Dick284

I agree.

You’d have to be getting into steeper than 30 degrees off of horizontal to make any difference on a 200 yd zero.

Just zero it and go.

Exactly

[justsomeguy]

Ron Spoomer has a good video on this subject….warning he talks about trigonometry for those who may suffer nightmares from high school math!

[Dom4]

Thanks again for all of the insight. I’ll go and sight it in on the flattest place I can find and go from there. Happy shooting.


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