Uphill vs. downhill shots.

carpediem

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Since I have for the last two years hunted on a pretty steep section of land, I was trying to remember what a guy said once about taking shots up or down hill. I seem to recall him saying to aim low up hill and aim high down hill. The one thing I don't recall him even mentioning was at what yardage does that even become a factor. Was he even correct? The last time I took a slope shot, it was down hill at short yardage and I didn't aim high per se. It was also a head on shot, so my target was pretty small. Anyone have any experience with this and am I reversing the two?
 
Greywolf224

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Interesting never gave this any thought. But as the second video stated, for the distance shooting that we do for hunting, say 75-150 yds does it really make enough difference to have to compensate for it.
 
Criticalt

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Ive been testing this with my 308. I havent shot very steep up or down but I have shot into and out of a pretty deep ravine. At short range it doesnt seem to make a difference 50-75 yards with 150 grain ammo.
Im going to find some longer range shots and ill report in.
 
meketrefe

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It doesn't matter uphill or downhill. If the angle and the distance are significant enough to make an actual difference in practical terms
then one should estimate base on a imaginary base at the level of the target from the point and are at and using the distance from where you
are to the target as the hypotenuse
of this imaginary triangle. You can use any trigonometrical formula that gives you that base distance.
Then use the resulting base as the effective distance to put your calculations.
Still you have to put the wind right and in hills or shooting across canyons can present some of the biggest challenges ever to ge the wind right. This will have a much bigger effect than most popular angle variants... but everything ads up.
 
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meketrefe

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Criticalt said:
Ive been testing this with my 308. I havent shot very steep up or down but I have shot into and out of a pretty deep ravine. At short range it doesnt seem to make a difference 50-75 yards with 150 grain ammo.
Im going to find some longer range shots and ill report in.
Click to expand...

It will be pretty hard to determine any variants at those distances. The difference will be negligible with such flat shooting cartridge and within
point blank range.

Things will get a bit more noticeable beyond point blank that should be 230-260 yards and depending on ammo and how you zero but will also need
a substantial angle like 40-60 degrees. Think about that imaginary triangle and how much distance and angle I need to put to create a substantial
difference between the direct sight and the effective range.
 
Greywolf224

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meketrefe said:
It doesn't matter uphill or downhill. If the angle and the distance are significant enough to make an actual difference in practical terms
then one should estimate base on a imaginary base at the level of the target from the point and are at and using the distance from where you
are to the target as the hypotenuse
of this imaginary triangle. You can use any trigonometrical formula that gives you that base distance.
Then use the resulting base as the effective distance to put your calculations.
Still you have to put the wind right and in hills or shooting across canyons can present some of the biggest challenges ever to ge the wind right. This will have a much bigger effect than most popular angle variants... but everything ads up.
Click to expand...

If I had to figure all this crap out while I was hunting, a fucking deer migration would run right past me before I figured out the angle of dangle.
 
1911guy

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Basically gravity is straight down for a bullet. So if it's 100 yards up or down a hill but a level distance would be 20 yards, the bullet drop would only be as far as it would be for 20 yards. That is slightly simplistic, but so close it's immaterial.
 
Snappo

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carpediem said:
Since I have for the last two years hunted on a pretty steep section of land, I was trying to remember what a guy said once about taking shots up or down hill. I seem to recall him saying to aim low up hill and aim high down hill. The one thing I don't recall him even mentioning was at what yardage does that even become a factor. Was he even correct? The last time I took a slope shot, it was down hill at short yardage and I didn't aim high per se. It was also a head on shot, so my target was pretty small. Anyone have any experience with this and am I reversing the two?
Click to expand...
 
meketrefe

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Normally nobody hunts far enough to worry about this and if the angle is too pronounced then better because it is like taking a closer shot. Still the time to target is similar and the wind effect during that time but drop is easy.
In other words, if one happened to lets say take
A shoot at 400 yards at 90 degrees just on top of us, drop will be same as at the muzzle that is zero yet the wind will be for 400 yards+.
Makes sense?
 
Snappo

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Greywolf224 said:
Hey

@Snappo you brought me back to SOH CAH TOA
I remember having to memorize a chart similar to that. Solve for the hypotenuse.
Click to expand...

Whenever my kids say "I will NEVER use trigonometry" I say "you will in USAF". Then they say "I will never use calculus" and I say "you will in electronics engineering technology". Now if they say "I will never use foreign languages" I can buy that.
 
Bushmaster

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A simple shooter error from treestands shooting down, is looking down on reticles, not looking through them. With ALL variables the same in gravity, ballistics, math etc...LOL..... Here ya go...








Shooting Uphill and Downhill
By
Major John L. Plaster, USAR (ret)
Of all the ways a precision rifleman must
compensate when firing – such as for distance,
for wind and for target movement – the most confounding and confusing is compensating
for shooting uphill or downhill. That’s because
it’s logical -- even ins
tinctive -- to lead a
moving target, to aim into a crosswind a
nd to hold high when shooting beyond your zero
distance. But shooting up or down? Many s
hooters find the whole concept contradictory
– the opposite of what they’d vi
sualize in their mind’s eye.
Let’s start with an expl
anation of what’s happening.
Say you’re tossing a softball underhand at
a milk carton 15 yards away. You naturally
understand that you must toss it a bit high so the
resulting arc allows it to descend and hit
the milk carton. That’s pretty understandable.
However, what if the carton is still 15
yards away by ground distance, but now it’s tw
o stories up, on a cliff? The same arc
above your line-of-sight that a
llowed your softball to hit th
e carton at ground level will
now cause it to pass over the milk carton – the
ground distance is stil
l 15 yards, but if you
use the same arc vis-a-vis the carton, you’ll miss it –
get it
? It’s simply that zeroing your
rifle over flat ground creates one arc, while
shooting up or down requires a slightly
different arc. The arc of a pr
ojectile crossing flat ground to
a target will not put that
projectile exactly on target when you’re ai
ming significantly uphill or downhill at that
same distance. The effect of this error increas
es with distance and st
eepness of angle to a
maximum of 60 degrees.
Counter-intuitively, this e
rror applies to shooting both
uphill and downhill. Whether
shooting an up
or
down slant, you must
hold low
to hit the target.
The Basic Rules
This can seem pretty confusing but ther
e’s the good news: You
don’t have to understand
the theory or my explanati
on – just faithfully apply the proper compensation and you’ll
be fine. Here are the basics
for up/down compensation:
1. At close range (100 yards or less) so little co
mpensation is required that it’s fine to just
aim dead-on, no matter the steepness of angle.
2. Up and down shooting both
require compensation, with th
e same amount needed for
45 degrees
up
as 45 degrees
down
, 30 degrees
up
as 30 degrees
down
, etc.
3. You always compensate by aiming LOW
. Keep this in mind by visualizing a limbo
dancer – YOU MUST AIM LOW --
Low, Low, Low
.
4. It’s easy to over-estimate the sharpness
of angle – be as exact as possible.
5. Your zero distance
is not an issue – the amount
of up or down compensation is
determined solely by the up/down a
ngle and distance to your target.
6. The amount of required comp
ensation increases significantly
with distance and
steepness of angle to a maximum of 60 degrees up or down.
Now, let’s look at some ways to
calculate the required compensation.
The Precision Solution
First, we’re going to look at the most
precise way to calculate the required up/down
compensation, and later, a simpler way. Our star
ting point is to find “Bullet Drop” for the
cartridge you’re firing. This is the ballis
tic measurement of how many inches a bullet
falls when the rifle is fired with its barrel perfectly parallel with the earth.
Many riflemen do not have access to this
data, although cartridg
e manufacturers have
it, and it can be found on-line, as well as in
any quality Exterior Ba
llistics program, such
as Sierra’s Infinity Program. Let’s assume
that you have Bullet Drop data – here’s what
to do with it.
To find up/down compensation, take the Bull
et Drop data (which is stated in hundreds
of yards) and multiple it by the factor
s in the accompanying chart, based upon the
steepness of angle to your target. For exampl
e, your target is 400 yards away, uphill 45
degrees, and you’re firing a .223 Remington, 69
-gr. Match round. You already have the
data that your Bullet Drop is 36.3 inches at
400 yards. Therefore, you multiply the 36.3
Bullet Drop inches by .293 and find you must
hold low 10.63 inches for a perfect hit.
It would be a tedious, slow process to
calculate this before each shot in a field
setting, so a smart
rifleman calculates
all the up/down compensation for his
cartridge at 100-yard increments, for
30 degrees, 45 degrees and 60 degrees,
puts it on a card and carries it with him.
Over time, he may even memorize it.
A less precise – but very fast –
alternative is to use a system I
UP / DOWN COMPENSATION FACTORS
5 Degrees: Drop Inches x .004
10 Degrees: Drop Inches x .015
15 Degrees: Drop Inches x .034
20 Degrees: Drop Inches x .060
25 Degrees: Drop Inches x .094
30 Degrees: Drop Inches x .134
35 Degrees: Drop Inches x .181
40 Degrees: Drop Inches x .235
45 Degrees: Drop Inches x .293
50 Degrees: Drop Inches x .357
55 Degrees: Drop Inches x .426
60 Degrees: Drop Inches x .500
developed, which I’ve dubbed, “Quick-Fix.”
“Quick-Fix” Compensation for Up/Down Shooting
I cannot take credit for i
nventing this brilliant means of up/down compensation since I
picked it up from the FBI. However, their
formula needed some tweaking so it cannot be
called the FBI Technique, either. I’ve named
it the Quick-Fix because you can calculate it
all in your head and adjust your
scope, or know how much to
hold low, about as quickly
as you read this sentence. It’s a compromise
on precision, but I think it more than makes
up for it in speed and simplicity.
Here’s how it works: You see a target at
500 yards that’s 30 degrees up or down. Shoot
it the same as if the target is on flat ground,
at 90 percent of that distance. This means,
treat it as a target at 450 yards – whethe
r you adjust an elevation knob or Bullet Drop
Compensator for 450 yards, or just use the
proper holdover for 450 ya
rds, you’ll hit very
close to true. The first Quick-Fix is:
Engage any 30 degree target as if it were 90
percent of its actual distance.
That’s easy enough to rememb
er and calculate in your
head.
When employed with .308 Cal. 168 gr. Match ammo, this 30 degree Quick Fix has a
maximum error of 4 inches at 600 yards, with
an average error of le
ss than 2 inches at
ranges less than 600 yards. That’s a gr
eat tradeoff of speed
for precision.
But earlier, didn’t I empha
size that Up / Down compensation requires holding low?
Absolutely. With Quick-Fix you’ll still be s
hooting low because you’ll be pretending the
target is closer than its actual dist
ance, and thus compensating by aiming low.
The other Quick-Fix is for engaging targets
that are 45 degrees up or down. In this case,
you shoot as if the targ
et is on flat ground,
at 70 percent of that distance
. This means treat
that 500-yard target as if it were on flat gr
ound and fire as if were 450 yards away. Thus
the second Quick-Fix is:
Engage any 45 degree target as
if it were 70 percent of its
actual distance
.
Out to 600 yards, firing .308 Winchester
168 gr. Match ammo, using 70 percent of the
distance, the maximum error is 4 inches, with
an average error of less than 3 inches. Not
a bad tradeoff of precision for
how quickly this can be done.
Well, then, what about shooting at 60 de
grees, where the uphill
/downhill effect is
greatest and requires the most compensation?
Bullet drop variances
are too great at 60
degree angles for a simple “Quick-Fix” rule-of-th
umb – but I’m not all that concerned.
Ask yourself, where would you fire at an angle
steeper
than 45 degrees? Carefully look
halfway from the ground to ver
tical – straight up – and cons
ider how truly steep is 45
degrees. When have you ever needed to take a sh
ot at a target more th
an 45 degrees up or
down? Most likely that would have been a crit
ter in a tree – but that
treed animal would
be less than 100 yards anyhow, and
not even require compensation.
Still, if it concerns you, you can take the
extra step of finding your
cartridge’s Bullet
Drop and use the “Up / Down Compensation Fa
ctors” listed above, and then actually
calculate the 60 degree compensation.
Happy shooting.
The End
 
Criticalt

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meketrefe said:
It will be pretty hard to determine any variants at those distances. The difference will be negligible with such flat shooting cartridge and within
point blank range.

Things will get a bit more noticeable beyond point blank that should be 230-260 yards and depending on ammo and how you zero but will also need
a substantial angle like 40-60 degrees. Think about that imaginary triangle and how much distance and angle I need to put to create a substantial
difference between the direct sight and the effective range.
Click to expand...
Yes, im not a long range shooter, im a hunter. I was just making sure I wont have any surprises. This is my first time hunting deer with a rifle. I have alot of open territory but also some steep hills and ravines. I wont even take a shot over 100 yards, there will be more chances.
The only reason im using the 308 this year is im getting tired of the sweet buck at 75 yards. With a shotgun they just walk off into the distance. This year, theyre going in the freezer.
 
carpediem

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Good information here for sure. I won't be overly worried about it from now on since the distances I take shots are nowhere near where this starts to impact the accuracy. I guess if I were hunting out west or Alaska this situation might be more of an issue.
 
meketrefe

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yes they are up there. Badger military grade, you know, take a bit advantage of that.
One can exchange the face to inidicate cosine and angle or whatever scale.
Bases and rings are bad ass though.
The horus and nightforce can be found on sale for about half of the badger.

Otherwise one can go old school...



Or metro-trendy school...

 
Jem45472

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meketrefe said:
It doesn't matter uphill or downhill. If the angle and the distance are significant enough to make an actual difference in practical terms
then one should estimate base on a imaginary base at the level of the target from the point and are at and using the distance from where you
are to the target as the hypotenuse
of this imaginary triangle. You can use any trigonometrical formula that gives you that base distance.
Then use the resulting base as the effective distance to put your calculations.
Still you have to put the wind right and in hills or shooting across canyons can present some of the biggest challenges ever to ge the wind right. This will have a much bigger effect than most popular angle variants... but everything ads up.
Click to expand...

Good God, does this mean aim high, or low :ROFL:
 
1911guy

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The only practical application for all this knowledge is in long range shooting. A sniper raking a long shot for example. Perhaps someone hunting long horn sheep in the mountains at long range. For most hunting situations it just flat ass doesn't matter.
 
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