zeroed in - bullet path

[graysoncountytexas]

hello to all!

If you have a properly zeroed AR, will the shots place just below POA at short ranges?

Thanks!

(and BTW, happy to be a member ;) )

[Oscar 319]

Y
e
s

[Failure2Stop]

Yes, distance at which the trajectory first crosses the line of sight is called the initial point, and will change depending on ammo, velocity, line of sight over bore, and zeroing distance.

Generally, the initial point with a 200 meter zero will be 50 meters - therefore all shots will be low out to 50 meters, then they will be high out to 200.
300 yards= 36 yards for initial point
100 yards= 100 Yards for initial point

Have fun

[graysoncountytexas]

ahhh, OK.

thanks!

[Dave L.]

Yes, distance at which the trajectory first crosses the line of sight is called the initial point, and will change depending on ammo, velocity, line of sight over bore, and zeroing distance.

Generally, the initial point with a 200 meter zero will be 50 meters - therefore all shots will be low out to 50 meters, then they will be high out to 200.
300 yards= 36 yards for initial point
100 yards= 100 Yards for initial point

Have fun

Certain carbine instructors advocate a 50 meter Zero (based on the above info for a fighting gun), correct?

[toddackerman]

Yes and no.

A POI sight in at 50 yds. will be 2.6" high at extremely close ranges. For example, a head shot at 7 yds needs to be aimed at the top of the hair line. It's somewhat important IMHO that you know the general POI's for your weapon from close in to 50 yds. 50 yds. being zero. This would equate to a 200 yd. zero.

[Dave L.]

Yes and no.

A POI sight in at 50 yds. will be 2.6" high at extremely close ranges. For example, a head shot at 7 yds needs to be aimed at the top of the hair line. It's somewhat important IMHO that you know the general POI's for your weapon from close in to 50 yds. 50 yds. being zero. This would equate to a 200 yd. zero.

Right- I usually put my sights at 25 meters(not optics), did it in the MC and still do; I have just heard of some civilian instructors teaching the 50meter way- which is what I may switch to on some of my guns because it makes sense to me.

[Jay Cunningham]

A 100m is a very useful zero... but the 50/200 is a more versatile zero. One of those "determine your needs" things.

[Wayne Dobbs]

Grayson County,

Here's a chart (from a Collin County boy) that should help you see the bullet path values. This assumes a 55 grain FMJ-BT (M193 style) bullet at 3000 fps in a rifle with the sights 2.6" above the boreline. All of that describes a typical AR:

Trajectory Output
Input Data
Manufacturer: Hornady Description: .224 dia. 55 gr. Full Metal Jacket Boat Tail W/C

Muzzle Velocity: 3000.0 ft/s Chronograph Distance: 10.0 ft

Sight Height: 2.60 in Sight Offset: 0.00 in
Zero Height: 0.00 in Zero Offset: 0.00 in
Azimuth: 0.00 MOA Elevation: 0.00 MOA
LOS Angle: 0.0 deg Cant Angle: 0.0 deg

Wind Speed: 10.0 mph Wind Angle: 90.0 deg
Target Speed: 10.0 mph Target Angle: 90.0 deg

Temperature: 59.0 °F Pressure: 29.92 in Hg
Relative Humidity: 0.0 % Altitude: 600 ft

Vital Zone Radius: 4.0 in Std. Atmosphere at Altitude: No
Corrected Pressure: Yes Target Relative Drops: Yes
Zero at Max. Point Blank Range: No
Calculated Parameters
Elevation: 5.66 MOA Azimuth: 0.00 MOA

Atmospheric Density: 0.07483 lbs/ft³ Speed of Sound: 1116.5 ft/s

Maximum PBR: 311 yds Maximum PBR Zero: 269 yds
Range at Max Height: 160 yds Energy at PBR: 451.1 ft•lbs

Sectional Density: 0.157 lbs/in²

Calculated Table
Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
(yds) (in) (moa) (in) (moa) (ft/s) (none) (ft•lbs) (s) (in) (moa)
0 -2.6 *** 0.0 *** 3013.3 2.699 1108.7 0.000 0.0 ***
10 -2.0 -19.4 0.0 0.1 2973.5 2.663 1079.6 0.010 1.8 16.8
20 -1.5 -7.1 0.0 0.2 2934.1 2.628 1051.2 0.020 3.6 17.0
30 -1.0 -3.2 0.1 0.3 2895.0 2.593 1023.4 0.030 5.4 17.1
40 -0.5 -1.3 0.2 0.5 2856.3 2.558 996.2 0.041 7.2 17.2
50 -0.1 -0.3 0.3 0.6 2818.0 2.524 969.6 0.051 9.1 17.3
60 0.2 0.4 0.4 0.7 2780.0 2.490 943.6 0.062 10.9 17.4
70 0.5 0.7 0.6 0.8 2742.3 2.456 918.2 0.073 12.9 17.5
80 0.8 1.0 0.8 0.9 2704.9 2.423 893.4 0.084 14.8 17.7
90 1.1 1.1 1.0 1.1 2667.8 2.390 869.1 0.095 16.8 17.8
100 1.2 1.2 1.2 1.2 2631.1 2.357 845.3 0.107 18.8 17.9
110 1.4 1.2 1.5 1.3 2594.6 2.324 822.0 0.118 20.8 18.0
120 1.4 1.1 1.8 1.4 2558.5 2.292 799.3 0.130 22.8 18.2
130 1.5 1.1 2.1 1.6 2522.6 2.259 777.0 0.142 24.9 18.3
140 1.4 1.0 2.5 1.7 2487.1 2.228 755.3 0.153 27.0 18.4
150 1.3 0.9 2.9 1.8 2451.8 2.196 734.0 0.166 29.2 18.6
160 1.2 0.7 3.3 2.0 2416.8 2.165 713.2 0.178 31.3 18.7
170 1.0 0.6 3.7 2.1 2382.0 2.134 692.8 0.190 33.5 18.8
180 0.7 0.4 4.2 2.2 2347.6 2.103 672.9 0.203 35.8 19.0
190 0.4 0.2 4.7 2.4 2313.4 2.072 653.5 0.216 38.0 19.1
200 -0.0 -0.0 5.3 2.5 2279.5 2.042 634.5 0.229 40.3 19.3
210 -0.5 -0.2 5.9 2.7 2245.9 2.012 615.9 0.242 42.7 19.4
220 -1.0 -0.4 6.5 2.8 2212.6 1.982 597.8 0.256 45.0 19.5
230 -1.6 -0.7 7.1 3.0 2179.5 1.952 580.0 0.269 47.4 19.7
240 -2.3 -0.9 7.8 3.1 2146.7 1.923 562.7 0.283 49.9 19.8
250 -3.0 -1.2 8.5 3.3 2114.2 1.894 545.8 0.297 52.3 20.0
260 -3.8 -1.4 9.3 3.4 2081.9 1.865 529.2 0.312 54.9 20.1
270 -4.7 -1.7 10.1 3.6 2050.0 1.836 513.1 0.326 57.4 20.3
280 -5.7 -2.0 11.0 3.7 2018.3 1.808 497.4 0.341 60.0 20.5
290 -6.8 -2.2 11.8 3.9 1986.9 1.780 482.0 0.356 62.6 20.6
300 -8.0 -2.5 12.8 4.1 1955.8 1.752 467.1 0.371 65.3 20.8
310 -9.2 -2.8 13.7 4.2 1925.1 1.724 452.5 0.387 68.0 21.0
320 -10.6 -3.2 14.7 4.4 1894.6 1.697 438.3 0.402 70.8 21.1
330 -12.0 -3.5 15.8 4.6 1864.4 1.670 424.4 0.418 73.6 21.3
340 -13.6 -3.8 16.9 4.7 1834.6 1.643 411.0 0.435 76.5 21.5
350 -15.2 -4.2 18.1 4.9 1805.1 1.617 397.9 0.451 79.4 21.7
360 -17.0 -4.5 19.2 5.1 1775.9 1.591 385.1 0.468 82.3 21.8
370 -18.8 -4.9 20.5 5.3 1747.1 1.565 372.7 0.485 85.3 22.0
380 -20.8 -5.2 21.8 5.5 1718.6 1.539 360.6 0.502 88.4 22.2
390 -22.9 -5.6 23.1 5.7 1690.5 1.514 348.9 0.520 91.5 22.4
400 -25.1 -6.0 24.5 5.9 1662.7 1.489 337.6 0.538 94.6 22.6

28 Jun 2008 07:32:25, JBM [http://www.eskimo.com/~jbm]

[Carlos]

go to gunsmoke.com and look at the trajectory charts they posted using Jim Ristow's "GunController" computer program. Viewing the charts will get you started in understanding bullet path, etc.

[graysoncountytexas]

Carlos and Wayne (my fellow Texan) -thanks for the info/charts!