Sight calculation help

[Kmrere42]

Hi,



I have a Remington 700 sps in .223,  and am putting iron sights on it for local competition. 

Sight radius is 32" and total adjustment for the rear sight that I have is .350" from stop to stop elevation and .215" windage.


how do I figure max range before run out of elevation adjustment.

3200fps  62gr fmjbt  .285bc. 
not M855



Thank you,

Paul

[White Foxx]

Hi Paul:

Not sure if I can help here, cause my math is real rusty....   Anyway, do you happen to know what the click adjustment size is?   and an actual sight height would be a big help.  Because the sight height changes the POI from the close one to the far one, if that makes any sense.  In other words, the amount of adjustment increases as sight height increases..  Simply put a scope sighted rifle sighted in at 25 yards will have a much higher trajectory than one with most open sights, as the open are around .75 inches and the scope is around 1.5 inches.  I guess I should say that then angle is steeper!

Anyway here is some data based on  the values you have supplies.  This info is based on a .75 inch sight height and on a 20 yard zero, and ½ minute clicks.

PAGE
 Name: 223                                        Ballistic Coeff: .2850
 Weight GRS: 62.00                                 Sectional Density: .177
 pellet Caliber: .224                               Cross Wind 10.0
 Barometric Pressure: 30.00     Shooting Angle: 00     Temp-F:  70
     
           Velocity    Energy       Impact      Scope       Drift
 
    Yards    FPS       FT-LBS       Inches      Clicks      Inches
                                   
       0     3200      1409.59       -0.75      N  0.0        0.00
      20    3129      1348.04       +0.00      dn 0.0        0.04
      40    3060      1288.80       +0.61      dn 2.9        0.14
      60    2991      1231.82       +1.07      dn 3.4        0.33
      80    2924      1176.98       +1.38      dn 3.3        0.58
     100    2858      1124.20       +1.52      dn 2.9        0.94
     120    2792      1073.39       +1.49      dn 2.4        1.39
     140    2728      1024.47       +1.28      dn 1.7        1.93
     160    2665       977.36       +0.88      dn 1.1        2.55
     180    2602       931.98       +0.29      dn 0.3        3.26
     200    2540       888.27       -0.49      up 0.5        4.05
     220    2479       846.16       -1.50      up 1.3        4.95
     240    2419       805.60       -2.72      up 2.2        5.94
     260    2360       766.62       -4.19      up 3.1        7.06
     280    2302       729.16       -5.92      up 4.0        8.31
     300    2244       693.15       -7.92      up 5.0        9.68
     320    2187       658.53      -10.20      up 6.1       11.17
     340    2131       625.24      -12.75      up 7.2       12.76
     360    2076       593.24      -15.60      up 8.3       14.47
     380    2021       562.47      -18.74      up 9.4       16.28
     400    1968       532.97      -22.24     up 10.6       18.25
     420    1915       504.66      -26.07     up 11.9       20.33
     440    1863       477.79      -30.34     up 13.2       22.63
     460    1813       452.25      -35.05     up 14.6       25.11
     480    1763       427.95      -40.21     up 16.0       27.77
     500    1715       404.82      -45.84     up 17.5       30.60
     520    1668       382.78      -51.93     up 19.1       33.59
     540    1621       361.77      -58.51     up 20.7       36.73
     560    1576       341.74      -65.56     up 22.4       40.00
     580    1531       322.62      -73.10     up 24.1       43.41
     600    1488       304.81      -81.38     up 25.9       47.10
 

I hope this gives you a start in the right direction!  If you can get an a click size, and how many you rear sight has I can give you better numbers.  Sorry but my brain won't connect with its trig-o-something any more!  I use to know how to do that stuff........  Anyway, I'm old what can I say?

White Foxx

Shoot Better @ thelonerifleman.com

[White Foxx]

Here is the math to get you sight angle, I hope

angle = Atn(SH / Rzero)    SH = sight height  Rzero = the distance to your front sight
angle = angle * 180 / 3.14159265358979

The above math gives us your sight angle which gives us an angle of .6266 based on your numbers of 32 inches and a height of .35 inches

The following math gets your bore line or your actual line of sight.  Your max height at that range that range.

D = distance in feet


angle = angle * 3.14159265358979 / 180  Pi times degrees of angle
angle = Tan(angle)
H = D * angle 
H = H * 12  converts Height into inches


Ayway that how you figure it out.  Least wise that is how I remember it all. I had to dig through all my old calculations to find this…..


White Foxx