Shooting up or downhill

[Silverado]

I argue that when shooting up or downhill, the shooter should hold lower on the target than when shooting level. Is this correct?

[eroyd]

Gravity will have a lessened effect on bullet trajectory when shooting both up and down hill.

[Myk]

Gravity always has the same effect unless you go to another planet to compare.

Gravity is a horizontal effect. It effects the bullet on the horizontal distance from here to there, not the diagonal distance you are looking at and judging by. Same effect but over less distance than you are seeing.

[longwinters]

With a rifle, dead on either way.

long

[Graybeard]

This really is what Polls are for. IT is just a straight forward question for which answers can be provided.

Theoritically if the angle is steep enough and the distance long enough you will need to aim lower regardless of up or down. It is simple geometry really.

However in real life situations it is not as easy an answer. If you are in a tree stand and a deer say is near you such that the angle is steep you will need to actually aim high on the body if it is down hill of you and low if it is uphill from you say on a ridge above you. The reason isn't the bullet path to deer but inside the deer as you want it to traverse the center of chest.

So to respond to the specific question you asked the answer is maybe.    Bullet drop WILL be less up hill or down hill if the distance is long and angle steep. BUT to say you aim LOWER on animal? Well now I dunno about that. Read above.

GB

[dakotashooter2]

The lyman reloading manual has a little information on this but when it is broken down is indicated that shots where the angle is under 15% and less than 200 yards will not change the inpact more than 1MOA. At 30% and 300 yards is were things statrt to get intresting.

[thecowboyace]

Also one must think of the speed of the bullet and weight.  Low speed, heavy bullet, requires more compensation than one would think.

[whitecloud]

Poll did not include dead on.I live in IN. so long and steep is far and few between.With my varmant rifles always dead on,but tey are light and fast.With my inline,still dead on.I have only had one shot that has been long and steep( 156 yrds/45deg).Hit right where I was aiming,(REALLY no kidden man!!!)Blew the heart out!!

[Larry Gibson]

I have not answered the poll because the answer is not there.

As Graybeard says the answer is not easy as there are many "ifs".  As also mentioned, when shooting uphill or downhill (it doesn't matter which)  gravity works on the horizontal distance not the gun/target distance.  There can be minute differences but they are not enough to effect most hunting situations.  For practical hunting, even of varmints, the difference is of little consequence.  Also as Graybeard said; extreme angles are also somewhat different but for practical angles here's how it works and how it gets confusing.

For the sake of discussion let's assume we are using a rifle with a 200 yard zero and are shooting a deer.  If the gun/target range is still within the horizontal zero range of 200 yards (regardless of angle and gun/target range to the deer) then hold dead on as you would normally.  

If you hold high you will hit high and if you hold low you will hit low. Lets say the gun/target range is 325 yards and the horizontal distance is 200 yards.  If we hold 12" high for 325 yards we shoot over the top of the deer.  If we hold dead on we kill the deer and the perception was we "held low" for a 325 yard shot.  If we really do hold low we shoot under the deer and the perception is we should have "held High.  A good case that perception is not always reality.

Now then, let's say the gun/target range is 450 yards and  the horizontal range is 300 yards.  If our rifle is a 30-06 and we are shooting 180s at 2650 fps then the bullet should drop about 35-38" at 450 yards.  If we hold over 35" then we will shoot way over the top of the deer  by about 20+" because the shot called for only 8-10" of actual hold over for the 300 yard horizontal range.  Again the perception is to "hold low", i.e. "lower" than we would have held for a 450 yard shot.  

However, when this discussion arises most do not deliniate that "hold low or high' refers to holding lower or higher from the amont of holdover we would have used for a gun/target range had the range been horizontal.  Many get further confused because they think "hold low or hold high" is taken from the point of aim on the deer.  Confused?  Don't feel bad, most are.

Years ago I developed a simple chart showing the "zero" or "hold over" to use when the gun/target range and angle above or below horizontal was known.  I have used it with both hunting and sniping and it has always worked when the angle of the shot wasn't more than 60 degrees above or below horizontal.  The chart works for all cartridges if you are using adjustable sights and know the range settings.  If you are using holdover you need to know the actual drop of the bullet past the zero range on a horizontal plane.   The trick is measuring the gun/target range accurately and measuring the angle within +/- 5 degrees.  The range part is now easy with laser range finders but the angle part can be difficult unless it is practiced.

Guess what I'm saying is there is no 'pat" answer whether you hold high or low as it depends on your perception of what high or low is and from what point of aim.

Larry Gibson

[Silverado]

I guess I should have edited to say "All else being equal..."  :roll:

Thanks for the input folks.

[Sourdough]

I shot at a whitetail buck this year, that was down hill from me I held low on the shoulder.  I saw the mud fly just over his back.  Afterwards I got down and measured the distance, Just under 200yards, I was shooting a 30-30.  After I got down to the location of the deer I had not realised how steep the incline.  I would not have thought a 30-30 would have shot that high at 200 yards.

[oso45-70]

lmg, finally some one hit the nail on the head, you will never know the hell i have had trying to get this point across, thank you.
best wishes and keep your powder dry, Joe

[onesonek]

As LMG pointed out, perception is the key. For sake of conversation. Over the years in talking with many guides and outfiitters, they claim most misses are over shot. Results from ill-perceived range or angle,and the hunter trying to "help the bullet too much". With that said, when I can't get a level (relatively) shot, I prefer to work the terrain from above my target. Mostly for safety reasons, but also I can see a missed shot impact better (sometimes). But for the most part, I set my firearms up on tight PBR's, and hunt within those limitations. Therefore lessening error, in range and angle estimation on my part.

[Sixshotbear]

:?: This is very interesting subject. I have been told all my life if you shoot up hill to aim high. If you shoot down hill to aim low. I have tryed this & some times it works & some times it don't. So I gues I don't know what to do. I hope someone does. Mybe it has more to do with yardage then up & down. :? :cb2:

[MGMorden]

The problem with up and down hill becomes the vectors.  With shooting straight, all energy from the projectile will be acting on the X plane, with gravity pulling down on the Y plane.  That's what a scope is generally set for.  However, if shooting downhill, you've got a portion of the energy acting on the X plane (not as much as normal), and then some pushing the bullet down on the Y plane.  This will cause the bullet to appear to drop a little faster, requiring a bit of hold over.

With shooting uphill, you've got some of the energy pushing the bullet higher on the Y plane, acting AGAINST gravity (when shooting flat the bullet does not work against gravity as the X and Y vectors are independent), requiring you to shoot just a wee bit lower than normal.

Now, practically, you can likely hold dead on and still make a killing shot, but for the sake of argument those would be the corrections needed.

[Larry Gibson]

MGMorden

Let me see if I understand; The bullet is slower shooting uphill and faster shooting downhill because of gravity?  

Well you seem to have the equation with the X, Ys and Zs so perhaps you could calculate what the remaining velocity of a 180 gr SP, BC of .45 and a muzzle velocity of 2700 fps. The target  is an actual 500 yards at a 45 degree shot up, an actual 500 yards horizontal shot and an actual 500 yards at a 45 degree shot down.  It would be interesting to know just how much faster or slower gravity makes the bullet over the horizontal remaining velocity.  Your assumption always sounds like a reasonable one but I've never been able to verify if there is a difference and if there is; that it makes any difference.

Larry Gibson

[Glanceblamm]

LMG
If I may jump in ahead here, I would say flatter on both accounts and forget about gravity induced speed.

If ya slap a level on your barrel and shoot straight up, theoretically the bullet would run out of steam and fall right back into the gun barrel.

Same with straight down. You would get a straight line although you wont get your bullet back this time.

If we then shoot horizontal, We now have a horrible curve at right angles to our nice straight lines.
As we elevate or lower the muzzle from the horizontal, our lines start getting flatter & flatter again making it nessary to Hold Low for high and low shots because we sighted in on the horizontal to begin with.

[Lee D.]

Glanceblam,
   That was the simplest and clearest expanation I have ever seen.  I've tried to explain this to people but now I will use your words.

[lilabner]

On a scope sighted rifle, the line of sight is higher than the rifle bore by a considerable amount. At short range, it is necessary to hold high to compensate for this, whether shooting uphill, downhill or on the level.  At longer ranges when shooting uphill or downhill, whether you hold high or low depends on the range of the target, the steepness of the slope  and what range the rifle is sighted in for. If the target is above or below you and a long way off, you may have to hold either high or low to hit the target. Depends on how far away it is on a horizontal plane between vertical lines drawn through you and through the target and whether you are sighted in for a shorter or longer range than that distance.
So, to sum up, it all depends.

[7magWoodsman]

I think that wind is the main factor, because depending on the angle wind could change 500 times up a bluff and as far as the scope setting higher on the barrel...is that not the reason we "zero" our scopes, to compensate for the difference in the line of sight?  If there is NO wind and you are shooting uphill at 150 yards and your rifle is sighted in at 150 yards you should hit right on target, although your bullet will hit at an angle, as far as gravity effect, the speed of a high-power bullet is so fast it will actually have to slow down a lot before it is "greatly" affected and also must be at a very "LONG" distance, as for arrows they "may" be affected by said gravity. I am no scientist or algebra/physics major but.....I think the majority of uphill/downhill misses come from lack of proper range assessment, and no consideration of conflicting windshifts that occur at even slight elevation changes...

[John Y Cannuck]

Low, but at most hunting ranges, the difference isn't worth correcting for, at least on big game, unless you hunt the mountains