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  • Adjusting for altitude?

    It's almost ELK hunting season!!! *wiggles excitedly* Well, I guess if you're bowhunting it already is, but my tag is for first season rifle.

    Here's the scenario. I live at elevation 4800 feet. I'll be hunting a few hours away at over 8000 feet, possibly above 9000. My rifle is a Colt Sauer 300 Win Mag. It was last sighted in near sea level, and not by me, so I know I'll be making some adjustments; I tend to sight in for 200 yards.

    If I sight in here at 4800', will I have any difficulty with accuracy at 8000'+? What kind of effect will +3500' elevation have, if any? Do I need to make some sort of adjustment for differences in altitude?
    Last edited by Reiland; 10-28-2008, 12:09 AM.

  • #2
    You shouldn't, It should be fine. You will have more of a problem with shooting up hill or down hill and bullet drop.
    The early bird may get the worm, but the second mouse gets the cheese.

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    • #3
      What's more important is to use the exact same ammo you sighted-in with to hunt. I"ve hunted with people that sighted- in with a factory load and than when we got to the hunting area, went to a sporting goods store to buy either another brand or different bullet weight. When their shot came, they missed. I adjust the scope to print 2.5 inches high @100yds. that will give you a dead-on hold out to about 400 yds. I use handloads when hunting. For the
      .300 Win. mag, a 180 grain hornady interlock or Nosler partition on top of 71 gr.of IMR 4350 gives me a little over 3000 FPS on the chronograph. ALWAYS aim your shot where you want the bullet to hit and practice from different positions. The only adjustment for altitude is the air is thinner and the climate is colder. I would be using magnum primers.Good luck.

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      • #4
        Don't worry about it. In Benchrest shooting we are concerned with altitude and density altitude, but we are looking for group shots of .1-.25" or so. Yes, the rifle will shoot different in higher elevation, but not enough to make a difference. Good luck hunting!
        "My faith, my country and my family will guide me; nothing more, nothing less" -Gen. Tommy Franks

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        • #5
          I see you live in western Colorado. If you get a chance, you could drive up to the mountains and see what your rifle does @ altitude. That way you would know exactly what to expect from your gear. Good luck.

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          • #6
            I'd be more worried about how you will function than I would the rifle. Altitude can be a real deterrent to your activities. I guess some of the CO folks can address that issue since that state has a lot of ups-and-downs. But if I remember my military training, even moderate changes in altitude (going above 7000 ft) can cause some problems if you're not acclimated.
            "Blaming the prince of the fools should not blind anyone to the vast confederacy of fools that made him their prince" - Unknown Author
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            "That government is best which governs the least, because its people discipline themselves." - Thomas Jefferson
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            • #7
              I live in the Black Hills (WY side) my house and range is at 4500 ft. I hunt the Big Horns at 9-10,000 feet. I cant see a differance in my rifles that would matter.

              An example, if you put a 180 grn 308 @ 3000 fps (your 300 wm), into a bal. calculator, assuming you sight it in at 250 yards, the total drop at 400 yards is 35 inches @ 4500 ft. and 35.8 inches at 10,000.

              Dont know about you but my eyes arnt good enough to measure 8/10s of a ft on an elk at 400 yards.

              So IMHO I suggest not worrying about it.

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              • #8
                FNA209, good point, but luckily the altitude is only an issue for me if I'm hoofing it in ski boots above 11,000 feet...which is a few months down the road

                This is the first time I'll have sighted in below 7000', so it's nice to know the elevation change shouldn't be a concern as far as rifle performance. Thanks for all the help, guys!!

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                • #9
                  Watch out for altitude sickness. I came down with it awhile back in Bridgeport humping up and down past 10K. (IIRC).

                  As far as the rifle, I would be worried about it if I was doing precision work or extended long range hunting. If that were the case, then I would check zero at base camp before I set out.

                  What is the longest shot you would make on an Elk?
                  "People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." - George Orwell
                  8541tactical.com - Ammo Wallets

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                  • #10
                    Originally posted by kraigwy View Post
                    I live in the Black Hills (WY side) my house and range is at 4500 ft. I hunt the Big Horns at 9-10,000 feet. I cant see a differance in my rifles that would matter.

                    An example, if you put a 180 grn 308 @ 3000 fps (your 300 wm), into a bal. calculator, assuming you sight it in at 250 yards, the total drop at 400 yards is 35 inches @ 4500 ft. and 35.8 inches at 10,000.

                    Dont know about you but my eyes arnt good enough to measure 8/10s of a ft on an elk at 400 yards.

                    So IMHO I suggest not worrying about it.

                    My first elk hunt I pulled a non-resident big game tag for Wyoming. Stayed with some friends in Upton and hunted mule deer in the Black hills Nat. forest. We were walking it out and they told me to head South. After a couple of hours , I found a fire watch station and waited a bit. My companions came along a little later and advised me I had walked over into South Dakota. The town I spotted off in the distance was Spearfish. We hunted elk out of Turpin, some of the most beautiful country i'd ever been in. No snow to push them down, but Good times and memories.

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                    • #11
                      Be sure to consider the applicability of the law of cosines when shooting up or down a slope (whether it's up or down makes an adjustment-worthy difference for some longer shots).

                      http://www.ballisticards.com/slopedoper.htm

                      Happy hunting.

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                      • #12
                        Let see, baseballs go futher, golf balls are straight gone and footballs get a bit lighter. There is some difference but the should be at greater distances. You should be just fine eith you zero at 200 and unless you plan on shooting past 3 or 400, you should not see much difference. Good luck.

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                        • #13
                          Your question is load and rifle dependant. There is no one equation that I'm aware of.

                          Slope firing:
                          slope range X COS of angle = Horiz. range.

                          Angle reading: 10 / 20 / 30 / 40 / 50 / 60 / 70 / 80 / 90
                          COS of angle: .98 / .94 / .85 / .75 / .65 / .5 / .35 / .2 / 0

                          Slope range is used for windage adj.

                          Bet ya wish ya paid better attention in math class now...

                          I know army scout snipers that have never heard of this equation. They don't use computers just simple calculatiors. If you really want to go overboard you can get a kessel 3000 weather computer which will give you most data that battleships use for 20 mile shots, save rotation of the earth. But you will need the equations to apply the weather data. Buck Rogers meets Elmer Fudd.....

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                          • #14
                            O.K. I just thought of an equation that might do what you are asking, but the amount of data you would need makes it impractical for field use.

                            Math was my worst subject so don't stand down range from me...

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                            • #15
                              Just get real close. It's easier to become invisible than it is to do the math Not A Cop just posted.

                              M-11
                              “All men dream...... But not equally..
                              Those who dream by night in the dusty recesses of their minds wake in the day to find it is vanity;
                              but the dreamers of the day are dangerous men,
                              for they act their dreams with open eyes to make it possible.....”

                              TE Lawrence

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