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Old 11-20-2019, 04:43 PM
walk in the woods walk in the woods is offline
 
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Default horizontal and vertical bullet drop

I am trying to get an idea of my likely at longer distances. The range where I am a member only has 100 yard range.

I am set 2 inch high at 100 yards. I am hitting within an inch most times with a rest.

Horizontal question - is horizontal error directly related to distance. For example if I am 1 inch right at 100 yards I think I should be 2 inches right at 200 and 3 inches right at 300 yards. Am I missing something?

Drop question - how accurate is the ballistic info that comes on the ammo case? That is the best I have for the moment.

Details - 30-06, 165 grain, Winchester Super-X, Powerpoint. Rifle is by Savage with a Vortex scope. Shooting on a bench rest or from prone with a backpack rest for results given above. Now have a range finder for accurate distances.

also any faith in this website? https://ballisticscalculator.winchester.com/#!/result
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Old 11-20-2019, 04:52 PM
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Sashi Sashi is offline
 
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Your definitely good for hunting.
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Old 11-20-2019, 06:18 PM
elkhunter11 elkhunter11 is offline
 
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The ballistic data printed on the ammunition box, or the manufacturers website, is only correct if the ammunition produces the same velocity in your rifle, which often isn't the case. It is also only accurate at the atmospheric conditions that the ammunition was tested at. You should be close enough for big game hunting to 300 yards or so, but I wouldn't trust it for shots at 400 yards or more, based only on shooting it at 100 yards.
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Old 11-20-2019, 07:05 PM
brewster29 brewster29 is offline
 
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[QUOTE=walk in the woods;4059430]I am trying to get an idea of my likely at longer distances. The range where I am a member only has 100 yard range.

I am set 2 inch high at 100 yards. I am hitting within an inch most times with a rest.

Horizontal question - is horizontal error directly related to distance. For example if I am 1 inch right at 100 yards I think I should be 2 inches right at 200 and 3 inches right at 300 yards. Am I missing something? QUOTE]

Your math is correct, 1 inch at 100 will equate to 2" @ 200, 3 @ 300, etc.
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Old 11-22-2019, 07:21 PM
dave99 dave99 is offline
 
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Default horizontal and vertical bullet drop

You are definitely on the right track in terms of both vertical and horizontal. Here is a bit more nuance:

Vertical: Ultimately, vertical drop is determined by flight time between muzzle and intended target. The greater the bullet travel time, the more vertical drop. Therefore, higher velocities will respond with less vertical drop, given the same distance travelled, simply because they arrive at the target sooner. The aerodynamics of a bullet (read: ballistic coefficient) affects velocity through drag, therefore affecting flight time (a round nose/flat base bullet with poor aerodynamics will quickly lose velocity, resulting in longer flight time than a spire point/boat tail bullet).

Horizontal: Your geometry is correct. A 1inch mistake at 100yds will be a 10inch error at 1000yds. Vertical or horizontal, the mistake will have the same result. It is a simple linear relationship. However, wind also can play a HUGE role in horizontal error (the horizontal turret on the scope is often called the windage turret for this reason). The effect of a consistent wind on a bullets horizontal flight path increases disproportionately as the distance increases (and as velocity decreases). As a result, the relationship between horizontal impact point and distance to target is not linear.

The stated ballistics on a box of ammo will be similar to that of your rifle, so long as the muzzle velocities are also similar. Often, they are not. The best way to verify point of impact and longer distances is to shoot paper at longer ranges.

For hunting purposes with your 2 inch high zero at 100yds, I would personally trust is to 250yds without further confirmation. Anything beyond 300yds, I would certainly recommend punching paper to confirm your POI.


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Last edited by dave99; 11-22-2019 at 07:28 PM.
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