The Saga Of The Uphill-Downhill Shot, Part I

Discussion in 'Technical Articles - Discussion' started by ADMIN, Jun 16, 2010.

  1. ADMIN

    ADMIN Administrator

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    This is a thread for discussion of the article, The Saga Of The Uphill-Downhill Shot, Part I, By Edd Pungubwe Woslum. Here you can ask questions or make comments about the article
     
  2. yobuck

    yobuck Well-Known Member

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    very good article. no doubt uphill/downhill shooting is more complex than most of us realize. im sure most hunters pay little attention to it.
    it is very important to take cousine into account when setting up for a shot. the longer the distance the more important it becomes.
    there are inexpensive ways of accuratly getting the information with basic tools and a prepared chart or a small calculator.
    it can become as complicated as we wish to make it. and it can change as wind and other conditions change.
    long range shooting is not an exact science, much as many think it is or might like it to be.
    the most important thing, as the auther pointed out, is the fact that a spotter is absolutly essential for successful long range hunting.
    both deer in the article were in fact taken. without the spotter that might not have been the case.
    there are lots of reasons why a shot could be a close miss. not the least of which could be an obscure branch.
     

  3. breakerbar

    breakerbar New Member

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    Hey Guys. I think this is simply a trigonometry equation. Gravity only effects the horizontal distance. For flat shooting gravity affects bullet the entire distance but uphill-downhill it only effects part of the shot. As you change the Shooting Angle the Distance Affected By Gravity changes.

    DOWN - Actual Distance x sin(shooting angle) = Distance Affected By Gravity
    UP - Actual Distance x cos(shooting angle) = Distance Affected By Gravity

    Lets use 400y@ 60d down. 400 x sin(60) = 346.4
    Adjust your scope for 346.4 yards
     
  4. ken snyder

    ken snyder Well-Known Member

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    The 2 previous posts are correct, good education and application of physics. The problem is extrapolated data vs. observable data. calculated is a static measurement or basically single point calculation. Bullet trajectory is dynamic ever changing and requires practically infinite points of calculation to arrive at an actual result and then that result is only valid for that exact set of variables. Direct observation can go backwards and correct itself with fudge factoring becoming dynamic, where math will insist that the bullet trajectory conforms to it, or becomes static. I can't think of a better science than optics manufacturers to help us out. They are 100% about observation ( no pun intended ). Hopefully they will come up with something that will allow tweeking in fudge factors.
     
  5. Alan Griffith

    Alan Griffith Well-Known Member

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    Is their going to be a Part II?

    If not, we could use a table in both ACI and degrees showing the percentage to subtract for the angled shot from the drop at full, zero degree, range.

    Alan
     
    Last edited: Apr 28, 2012
  6. Big John 50

    Big John 50 Member

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    Gotta chime in on this one!

    Agreeing that uphill and downhill doping require the same logic and practice to resolve, what I read in the correct and incorrect application examples is curious.

    The story is about the practice of range doping (on game twice and then on a paper target), bullets struck some 6" high using the TBR data. Yet in the Correct/Incorrect section the correct doping would result in a bullet strike 7 clicks higher than the incorrect doping. Assuming 1/4" per click @ 100yds that translates to a 7" higher bullet strike than the incorrect doping.

    I'm not trying to be argumentative here, just help me out, wasn't the original problem with bullets striking 6" too high?

    If I've misunderstood then my apologies to the author and I will more thoroughly re-read whatever is suggested.

    All of that said, I must confess that I have never shot at game over 100 yards from anything above about 15 - 20 degrees--not enough range or elevation difference to matter. My want and dream though is to go sit on the edge of the Caprock here in Texas and pop off a few rounds to get some of the elevation and distance experience discussed in the article.
     
  7. Farmer Rob

    Farmer Rob Active Member

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    If I can jump im and give my 2 cents.

    A bit of history, i live and hunt in the mountains, from 500m to 1000m height and i encountered this phenomenon too.

    Firstly uphill or down the 6 inch high is correct and the calc by bigred proved it.

    As i understand it, shooting at a great angle uphill the projectile is not flatbut angled up, well der!!!

    so if a projectile is 20mm long but angled at 45 degrees it is only say 15mm across if you were to look straight down on it, therefore it is 25% smaller.
    This wont reduce the gravity by 25% because the weight etc is the same but it will affect it.

    Rob
     
  8. Big John 50

    Big John 50 Member

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    As Farmer Rob says, the 20mm length projectile on a 45 degree angle casts a projection of 15mm length (simple HS geometry points toward that figure, actually it would be 20mm/sq root of 2 = ~14.2mm). Calculating a projection doesn't address my question though.

    Since we are on the topic of HS geometry let's briefly consider: Assuming a 30 degree elevation slope suggests using a 30-60-90 triangle--height above/below the shooter is the short leg, the second leg is sq root of 3 x first in length, the hypotenuse (actual sight line) is 2 x the first leg. Therefore, the doping adjustment for a 400 yd sightline can be calculated as 200 x 1.73 = 346 yd. Gee!! Ain't that whut the TBR sed?

    Obviously, the TBR uses HS trigonometry and geometry for its doping suggestions. Now that I've layed out my background thinking we'll get back to my respctful question: When the incorrect method (as employed inside the TBR) puts bullets 6" too high why then would anyone use a "correct" method of doping that puts bullets even higher above target?

    Some dogs learn that chasing its tail is fruitless, others do it for fun occassionally, others do because they don't know better. Which kind of shooter do you want to be?
     
  9. 25.06

    25.06 Member

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    Good Afternoon'

    I would like to participate in this conversation. Unfortunately, I don't know how to insert an Excel spreadsheet I created called " Shooting Angle Matrix ".
    I have always thought, a direct range to the target multiplied by an angle multiplier, base on the degree of angle. This would give you the Gravity Range, reflecting the difference.
    I,E,. A direct range of 400 yards at a 40 degree angle would compute to 308 yards and your scope could be adjusted accordingly. ( the Multiplier for a 40 degree angle is .77 400 X .77 = 308 yards.
    If this is not correct, I guess I need to rework my Matrix. Currently, I print it at 60% laminate it and carry it in my pocket for ranges to 500 yards with up to 60 degress angle calculations with each cell in the matrix calculating gravity ranges. So, could someone direct me to directions on " How To"
    Please reply:
     
  10. Big John 50

    Big John 50 Member

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    I've been asked to resign or been fired from four jobs because I call it the way I see it. Same situation here, anecdotal stuff is good to hear, fun to read and can guide another's practice in LR application of their weapon(s).

    Again, my question, not yet answered, why would any one advocate for a method of doping which creates an even greater error in shot placement in the same direction as the original error?

    Compare apples to apples here, same angles, distances, etc. Does anyone out there have a data driven comment, charts and graphs with lased distances to bring to this question?

    If not, we are left with the 1850s technology of shooting your hunting iron a bunch in different situations and keeping pencil/paper notes.

    What we can deduce from the TBR and HS geometry is that they are both helpful aids toward getting closer to a kill-shot. What I would like to personalize is this: shooting at a target 400 yds sightline away which is 200 yds!! (600 feet) above/below you..... Well, I think you get my point. Hell, either shot, 200 yds or 400 yds, over level terrain requires skills most mortals never strive to develop fully. Put that scenario across the bottom of a canyon where wind, thermals and adrenaline jitters become blended......who in their right mind would take that shot unless they had specifically practiced it? Not me.

    I shot a LR qualifying score at 300 yds near Houston, TX during Tropical Storm Charlye in 1998, 4 inch group in the bullseye, over level ground with 190gr SMK out of a '17 Enfield, all original. Still carry the approval card in my wallet today. On other days under light breezes Kentucky was still about 14" and Tennessee was about 16-17" at 400yds over flat ground to hit the gong--aim at the base of the skull to plant the pill in the vitals or dial in a similar doping.

    Point: take the shots you've practiced, to practice on game may turn out ok but is still a gamble with the game's life or suffering.
     
  11. joe0121

    joe0121 Well-Known Member

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    Bottom line. Nothing beats good DOPE(Data on Previous Engagements).

    A bullet does not follow a strait line or even an angled line. It's flight is parabolic. So if you need say a 10% adjustment at 300 yards you might need a 60% adjustment at 900. As the bullet slows it's angle of flight increase disproportionately to the shooting angle.



    This is why these little quick tricks might get you close but not perfect.
     
  12. Big John 50

    Big John 50 Member

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    D.O.P.E., I gotta remember that one!!

    Thanks for your service!
     
    Last edited: May 12, 2012
  13. joe0121

    joe0121 Well-Known Member

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    Thank you :)