Bullet path height question

[KDX]

I have a Leupold RXII rangefinder on the way and was wondering how to find the bullet path @ 500 yards (not bullet drop) for a .223 52gr Hornady match HPBT (25.5gr Benchmark) traveling at about 3200-3250fps with a sight in of 200 yards. The reason I'm asking is because the rangefinder has TBR and will give you the hold over for targets once you know this information.

Dial in your RX to one of seven TBR™ ballistics settings for the rifle and three for the bow for incredible accuracy. TBR is effective to 800 yards for most rifle cartridges. The RX has three True Ballistic Range readouts for rifle hunters.

MOA: The minutes of angle of elevation to adjust your riflescope for precise zero.

HOLD: The number of inches or centimeters to hold over or under aim point on target.

BAS: The equivalent horizontal range for which you should hold for use with your bullet’s or arrow’s ballistics.

I don't expect to nail gophers @ 500 yards, but some help with coyotes at longer ranges would be nice.

 

[maynard]

Bullets are dropping when they leave the barrel. So you will need to know the drop from 200-500.
Try w ww.eskimo.com/~jbm/calculations/traj_basic/traj_basic.html

 

[roberti11]

Shooting at Angles

I think what you are asking is answered here.

The TBR option on the leupold rangefinder makes these corrections for you according an approximation of the bullet velocity, there are 4 ranges of bullet velocities to choose from.

Since TBR also gives you the angle of the shot, you could use a calcualtor and work this out on your own for the exact velocity of your load.

See the following link...

http://www.snipertools.com/article5.htm

 

[Curt]

I thought bullets climbed initially when they left the barrel, peaking above line of sight somewhere downrange and then starting their rapid descent back to the earth.... Am I OTFL??

 

[maynard]

I thought bullets climbed initially when they left the barrel, peaking above line of sight somewhere downrange and then starting their rapid descent back to the earth.... Am I OTFL??

Took me a minute to figure it out, but yup you are OTFL
How could the bullet go up? If you canted the rifle 90 degree left or right would the bullet still go up?

 

[KDX]

Bullets are dropping when they leave the barrel. So you will need to know the drop from 200-500.
Try w ww.eskimo.com/~jbm/calculations/traj_basic/traj_basic.html

That's a pretty cool site, thanks for the link.

 

[roberti11]

Bullet path

I thought bullets climbed initially when they left the barrel, peaking above line of sight somewhere downrange and then starting their rapid descent back to the earth.... Am I OTFL??

No you are not OTFL, when you shoot at a distant object your bullet travels in an arc. If you are shooting a 175gn match 308 bullet at 2650fps at a target 1000 yards away, you need to crank 42 minutes of elevation, that means you are aiming at a point 35 feet above the target, the bullet is falling as soon as it leaves the bbl, so you shoot in an arc, in reality when the bullet is at the 500 yard mark, it is still some 15 feet above the ground, as it falls toward the target. If you want to prove this, take a rifle sighted at 100 yards, and then shoot a large paper target at 25,50,75 yards, if you aim at the same dead centre point the holes will be higher at 50 than at 25 or 75 yards, that is because at 25 the bullet is on its way up, at 50 it is at max, and at 75 it is on its way down.

This link
http://www.snipertools.com/article5.htm

Talks about how to correct for shooting at things that are either up hill, or downhill, because at long distances there is a significant difference between the horizontal distanct to the object and the direct distance you would measure with a mil dot, or range finder.

 

[bob21bobby]

I don't think a lot of people are thinking about this the right way. The ONLY time a bullet will hit directly in front of the muzzle, if is the target is about an inch or two away, any further and the bullet starts to drop. When you are using your sights, (NOT a bore sight), the sight angle takes this into account, so that if you drew a straight line between the front and back sight, and a line along the muzzle bore, they would NOT be parallel. The sight is a way of figuring out the cosine of the drop in a dependable manner FOR ONE RANGE ONLY. Yes the bullet does start dropping as soon as you fire, but the muzzle is canted up at the angle needed to intersect the target at any given range...ie: an arc. So a few yards in front of the muzzle the bullet is still going up as per the instructions YOU are giving it by means of the sight. And you though that you forgot all your high school trig. LOL

 

[maynard]

No you are not OTFL, when you shoot at a distant object your bullet travels in an arc. If you are shooting a 175gn match 308 bullet at 2650fps at a target 1000 yards away, you need to crank 42 minutes of elevation, that means you are aiming at a point 35 feet above the target, the bullet is falling as soon as it leaves the bbl, so you shoot in an arc, in reality when the bullet is at the 500 yard mark, it is still some 15 feet above the ground, as it falls toward the target. QUOTE]

Actually your barrel is pointing 35ft above the target, your sights are on the target. The bullet never rises above the line of the bore when it is fired however it does rise above the line of sight.
If you were to shoot a laser down the bore to the target the bullet would only hit the spot a very close range. POI would be lower as range increases.

 

[Curt]

So the bullet is climbing relative to the horizontal line of sight, but falling in relation to the tilt of the barrel, or exit angle.....

 

[roberti11]

No you are not OTFL, when you shoot at a distant object your bullet travels in an arc. If you are shooting a 175gn match 308 bullet at 2650fps at a target 1000 yards away, you need to crank 42 minutes of elevation, that means you are aiming at a point 35 feet above the target, the bullet is falling as soon as it leaves the bbl, so you shoot in an arc, in reality when the bullet is at the 500 yard mark, it is still some 15 feet above the ground, as it falls toward the target. QUOTE]

Actually your barrel is pointing 35ft above the target, your sights are on the target. The bullet never rises above the line of the bore when it is fired however it does rise above the line of sight.
If you were to shoot a laser down the bore to the target the bullet would only hit the spot a very close range. POI would be lower as range increases.

You are correct, my mistake, the cross hair is on the target but the bbl is pointing at a point above the target. Thanks for pointing that out.

 

[todbartell]

if you can range coyotes @ 500y with a RXII I would be amazed. I tested a RXIII one hunt and it wouldnt range a tree past 800y. Overall, a complicated and clutted unit which I was not impressed with. Funny thing is I had an RXIV on order from the US but it was backordered, Im glad I got to test the RXIII before it was shipped as it gave me time to cancel the order and purchase a Bushnell Elite 1500 ARC which is 3x as good

rant off! enjoy your RXII

 

[Silverado]

Tabular trajectory data at Non-Std. Atmosphere
Gunsite altitude : 1211 ft.
Air density : 0.076337 lb./ft³
-------------------------------------------------------------------------------------
Gun / Ammunition :
Bullet : .224, 52, Hornady BTHP M 2249
Bullet weight : 52 grains or 3.37 Grams
Muzzle velocity : 3225 fps
Crosswind speed : 10 Mph
Ballistic Coefficient(s) (G1):
C1=0.229@V>0 fps;


Optimum trajectory information :
Optimum sight-in range (X) = 266 Yds.
with max. ordinate above LOS at range (M)= 156 Yds.
and max. point blank range (P)= 307 Yds.
-------------------------------------------------------------------------------------
Sight-in clicks, 1 click = 0.665 cm/100 yd. or 0.262 in/100 yd.
Height of sight above bore axis = 5.08 cm or 2.00 inch
Gun is zeroed-in at 200 yds,
by sighting-in at level firing
-------------------------------------------------------------------------------------
Range Velo Time of Energy Path Deflection Total Sight correction Target
city flight to at crosswind drop for setting new lead
LOS of 10.0 Mph zero range 33 fps
-------------------------------------------------------------------------------------
·Yards fps s ft.lbs. in. in. MOA in. Clicks MOA yds ·
-------------------------------------------------------------------------------------
| 0 3225 0.0000 1201 -2.0 0.0 ----- 0.0 ------ ----- 0.00
| 10 3181 0.0094 1168 -1.5 0.0 0.15 0.0 +57.7 +14.42 0.10
| 20 3136 0.0189 1136 -1.1 0.1 0.25 0.1 +20.2 +5.04 0.21
| 30 3093 0.0285 1105 -0.6 0.1 0.35 0.2 +8.1 +2.02 0.31
| 40 3050 0.0383 1074 -0.3 0.2 0.45 0.3 +2.4 +0.60 0.42
| 50 3007 0.0481 1044 +0.1 0.3 0.55 0.4 -0.7 -0.18 0.53
| 60 2965 0.0582 1015 +0.4 0.4 0.66 0.6 -2.6 -0.64 0.64
| 70 2923 0.0683 986 +0.7 0.6 0.77 0.9 -3.7 -0.92 0.75
| 80 2881 0.0787 959 +0.9 0.7 0.89 1.2 -4.3 -1.08 0.86
| 90 2840 0.0892 932 +1.1 1.0 1.02 1.5 -4.6 -1.15 0.98
| 100 2800 0.0999 905 +1.2 1.2 1.15 1.8 -4.7 -1.17 1.09
| 110 2759 0.1107 879 +1.3 1.5 1.28 2.2 -4.6 -1.15 1.21
| 120 2719 0.1217 854 +1.4 1.8 1.41 2.7 -4.4 -1.09 1.33
M 126 2696 0.1284 839 +1.4 2.0 1.49 3.0 -4.2 -1.05 1.40
| 130 2680 0.1329 829 +1.4 2.1 1.55 3.2 -4.0 -1.01 1.45
| 140 2640 0.1442 805 +1.3 2.5 1.68 3.8 -3.6 -0.91 1.58
| 150 2602 0.1557 782 +1.2 2.8 1.81 4.4 -3.2 -0.79 1.70
| 160 2563 0.1673 759 +1.1 3.2 1.94 5.0 -2.6 -0.65 1.83
| 170 2525 0.1790 736 +0.9 3.7 2.07 5.7 -2.0 -0.51 1.96
| 180 2487 0.1909 714 +0.7 4.1 2.19 6.5 -1.4 -0.35 2.09
| 190 2449 0.2029 693 +0.4 4.6 2.31 7.3 -0.7 -0.18 2.22
X 200 2412 0.2152 672 0.0 5.1 2.45 8.1 0.0 0.00 2.35
| 210 2375 0.2277 651 -0.4 5.7 2.59 9.1 +0.8 +0.19 2.49
| 220 2338 0.2404 631 -0.9 6.3 2.73 10.1 +1.6 +0.39 2.63
| 230 2302 0.2534 612 -1.5 6.9 2.88 11.1 +2.4 +0.61 2.77
| 240 2266 0.2666 593 -2.1 7.6 3.04 12.2 +3.3 +0.83 2.92
| 250 2230 0.2800 574 -2.8 8.4 3.19 13.4 +4.2 +1.06 3.06
P 259 2199 0.2923 558 -3.5 9.0 3.33 14.6 +5.1 +1.27 3.20
| 260 2195 0.2936 556 -3.5 9.1 3.35 14.7 +5.2 +1.30 3.21
| 270 2160 0.3075 539 -4.4 9.9 3.51 16.0 +6.2 +1.54 3.36
| 280 2125 0.3215 522 -5.3 10.7 3.66 17.4 +7.2 +1.80 3.52
| 290 2091 0.3357 505 -6.2 11.6 3.82 18.9 +8.2 +2.05 3.67
| 300 2057 0.3501 488 -7.3 12.5 3.98 20.5 +9.3 +2.32 3.83
| 310 2023 0.3647 472 -8.4 13.4 4.14 22.1 +10.4 +2.59 3.99
| 320 1990 0.3795 457 -9.6 14.4 4.30 23.8 +11.5 +2.87 4.15
| 330 1956 0.3944 442 -10.9 15.4 4.45 25.6 +12.6 +3.15 4.31
| 340 1923 0.4097 427 -12.3 16.4 4.62 27.5 +13.8 +3.44 4.48
| 350 1890 0.4254 413 -13.8 17.6 4.79 29.5 +15.0 +3.75 4.65
| 360 1858 0.4414 399 -15.4 18.7 4.97 31.6 +16.3 +4.07 4.83
| 370 1827 0.4578 385 -17.1 20.0 5.16 33.8 +17.6 +4.41 5.01
| 380 1795 0.4746 372 -18.9 21.3 5.36 36.1 +19.0 +4.75 5.19
| 390 1765 0.4916 360 -20.8 22.7 5.55 38.6 +20.4 +5.10 5.38
| 400 1734 0.5090 347 -22.9 24.1 5.75 41.2 +21.9 +5.47 5.57
| 410 1705 0.5267 335 -25.1 25.6 5.96 43.9 +23.4 +5.84 5.76
| 420 1675 0.5446 324 -27.4 27.1 6.16 46.7 +24.9 +6.23 5.96
| 430 1646 0.5629 313 -29.8 28.7 6.37 49.6 +26.5 +6.62 6.16
| 440 1617 0.5814 302 -32.4 30.3 6.57 52.7 +28.1 +7.03 6.36
| 450 1589 0.6001 291 -35.0 31.9 6.78 55.8 +29.7 +7.44 6.56
| 460 1560 0.6191 281 -37.8 33.6 6.99 59.1 +31.4 +7.85 6.77
| 470 1533 0.6383 271 -40.8 35.4 7.19 62.6 +33.1 +8.28 6.98
| 480 1505 0.6578 262 -43.8 37.2 7.40 66.1 +34.9 +8.71 7.19
| 490 1479 0.6776 253 -47.0 39.0 7.61 69.8 +36.6 +9.16 7.41
| 500 1453 0.6979 244 -50.4 41.0 7.83 73.7 +38.5 +9.63 7.63
| 510 1427 0.7187 235 -54.0 43.0 8.05 77.8 +40.4 +10.11 7.86
| 520 1403 0.7400 227 -57.8 45.1 8.28 82.1 +42.5 +10.61 8.09
| 530 1379 0.7617 219 -61.8 47.3 8.52 86.6 +44.5 +11.13 8.33
| 540 1355 0.7838 212 -66.0 49.5 8.76 91.3 +46.7 +11.67 8.57
| 550 1332 0.8062 205 -70.4 51.8 9.00 96.2 +48.9 +12.22 8.82
| 560 1310 0.8289 198 -74.9 54.2 9.24 101.3 +51.1 +12.78 9.07
| 570 1288 0.8520 192 -79.7 56.6 9.49 106.6 +53.4 +13.35 9.32
| 580 1267 0.8754 185 -84.6 59.1 9.73 112.0 +55.7 +13.94 9.57
| 590 1247 0.8992 179 -89.9 61.7 9.98 117.7 +58.2 +14.54 9.83
| 600 1227 0.9234 174 -95.3 64.3 10.23 123.7 +60.7 +15.17 10.10
| 610 1208 0.9481 169 -101.0 67.0 10.49 129.9 +63.2 +15.81 10.37
| 620 1190 0.9731 164 -107.0 69.8 10.74 136.4 +65.9 +16.48 10.64
| 630 1173 0.9985 159 -113.2 72.6 11.00 143.1 +68.6 +17.16 10.92
| 640 1156 1.0243 154 -119.6 75.5 11.26 150.1 +71.4 +17.85 11.20
| 650 1140 1.0504 150 -126.4 78.4 11.52 157.3 +74.3 +18.57 11.49
| 660 1125 1.0769 146 -133.4 81.5 11.79 164.8 +77.2 +19.30 11.78
| 670 1111 1.1037 143 -140.7 84.6 12.05 172.7 +80.2 +20.06 12.07
| 680 1097 1.1309 139 -148.3 87.7 12.32 180.8 +83.3 +20.83 12.37
| 690 1084 1.1584 136 -156.2 90.9 12.58 189.2 +86.5 +21.62 12.67
| 700 1072 1.1862 133 -164.4 94.2 12.85 197.8 +89.7 +22.43 12.97
| 710 1060 1.2143 130 -172.9 97.5 13.11 206.8 +93.0 +23.25 13.28
| 720 1049 1.2428 127 -181.7 100.8 13.38 216.1 +96.4 +24.09 13.59
| 730 1038 1.2715 125 -190.8 104.3 13.64 225.7 +99.8 +24.95 13.91
| 740 1028 1.3005 122 -200.2 107.7 13.90 235.7 +103.3 +25.83 14.22
| 750 1018 1.3299 120 -209.9 111.3 14.17 245.9 +106.9 +26.73 14.54
| 760 1009 1.3595 118 -220.0 114.8 14.43 256.5 +110.5 +27.64 14.87
| 770 1000 1.3895 115 -230.4 118.5 14.69 267.4 +114.3 +28.57 15.20
| 780 991 1.4194 113 -241.0 122.1 14.95 278.5 +118.0 +29.50 15.52
| 790 983 1.4496 111 -252.0 125.8 15.21 290.0 +121.8 +30.45 15.85
| 800 974 1.4803 110 -263.3 129.6 15.46 301.8 +125.7 +31.43 16.19
| 801 974 1.4833 109 -264.5 129.9 15.49 303.0 +126.1 +31.53 16.22
-------------------------------------------------------------------------------------
M = Peak vs. L.O.S, X = Set Zero, P = Max. Point Blank Range
Elevation above Angle of Site (0.0 deg.) = 0.0806 deg.

 

[Silverado]

There ya go

 

[KDX]

Thanks Silverado.

f you can range coyotes @ 500y with a RXII I would be amazed. I tested a RXIII one hunt and it wouldnt range a tree past 800y. Overall, a complicated and clutted unit which I was not impressed with. Funny thing is I had an RXIV on order from the US but it was backordered, Im glad I got to test the RXIII before it was shipped as it gave me time to cancel the order and purchase a Bushnell Elite 1500 ARC which is 3x as good

rant off! enjoy your RXII
10-31-2007 07:19 PM

I don't think I could hold it on a coyote @500 yards, but I'm sure I could find a bale or brush near to one. Reading the instructions it doesn't seem to complicated, you just have to take the time to read and comprehend. I'm sure the ARC 1500 is OK, but Bushnell states it will range a deer to 500 yards and the RXII is rated for the same yardage. I paid less than half the price of the ARC for mine so I can live with that.

 

[todbartell]

trust me, I set up the RXIII and programed it, it just took 30 mins of screwing around to get it ready to work

Ive ranged trees out to 1200-1400 yards with my 1500 ARC and deer out to 600 yards. Good luck with your $250 RXII let us know how it works!