Advanced Marksmanship On the fly Uphill & Downhill shot formulas

#2
Re: On the fly Uphill & Downhill shot formulas

corrected comeups = cos angle*flat range comeups
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#3
Re: On the fly Uphill & Downhill shot formulas

10 degrees= one tenth of distance less (1%)
example:1000 yards at 10 degrees would require drop of 990 yards
20 degrees= six % less distance
example:1000 yards at 20 degrees would require drop of 940 yards
30 degrees = 15 % less distance
example:1000 yards at 30 degrees would require drop of 850 yards
45 degrees = 30% less distance
example:1000 yards at 40 degrees would require drop of 700 yards

note: These are rough estimates...
 
#5
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dunes450r</div><div class="ubbcode-body">interesting, how complicated or the actual formulas? </div></div>
Its actually really simple... Its based of physics equations

you take the measured distance and multiply it by cos(DEGREES of hill). Make sure your calculator is in degrees mode and not radian mode and your good to go.
 
#6
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: timelinex</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dunes450r</div><div class="ubbcode-body">interesting, how complicated or the actual formulas? </div></div>
Its actually really simple... Its based of physics equations

you take the measured distance and multiply it by cos(DEGREES of hill). Make sure your calculator is in degrees mode and not radian mode and your good to go. </div></div>
gotcha, basically all the formula is doing is just converting slope distance to horizontal distance?
 
#7
Re: On the fly Uphill & Downhill shot formulas

Exactly, you correct LOS range to horizontal range. If you google the "rifleman rule" it gets more indepth for ya. It works the same for up hill and down hill shots, most people correct the range then favor low.
 
#10
Re: On the fly Uphill & Downhill shot formulas

The Hillbilly way is make your own device, that attaches to your scope rail that reads out in percentage of change instead of angle.
 
#11
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gunfighter14e2</div><div class="ubbcode-body">The Hillbilly way is make your own device, that attaches to your scope rail that reads out in percentage of change instead of angle. </div></div>

they already make that, called an ANGLE COSINE INDICATOR, the new versions don't read the angle but the cosine so it's just the percentage of the dope based on the indicator.
 
#12
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rickp</div><div class="ubbcode-body">I've seen a lot of formulas for dealing with wind.

Are there any similar simple, somewhat on the fly formulas for making uphill or downhill shots?

Thanks </div></div>

the larger question is where are you going to need this in FL...???...???
 
#13
Re: On the fly Uphill & Downhill shot formulas

For inside of 500 yards hold bottom of the rib cage and send it. Works on vertical as well as horizontal rib cages.

If you wish to be precise there are 3 currently accepted rules.

Rifleman's

Improved Rifleman's

and the formula Sierra uses. The Sierra rule is very precise but you need pre printed dope cards for altitude, temp etc.

Quick and dirty, see line one. If you really want precision do the home work.

Cheers,

Doc
 
#14
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gunfighter14e2</div><div class="ubbcode-body">The Hillbilly way is make your own device, that attaches to your scope rail that reads out in percentage of change instead of angle. </div></div>

they already make that, called an ANGLE COSINE INDICATOR, the new versions don't read the angle but the cosine so it's just the percentage of the dope based on the indicator. </div></div>

You mean my 60's toy car tire an axle, that's weighted is out dated? Who has one w/large print?
 
#15
Re: On the fly Uphill & Downhill shot formulas

For the not so "on the fly" guys

The sierra formulas.

((((Bullet Drop (+) * (1.0 - cosine of angle)) + Bullet Path) / ((Range/100)*1.047)/3.438) = Corrected MIL Sight Adjustment

((((Bullet Drop (+) * (1.0 - cosine of angle)) + Bullet Path) / ((Range/100)*1.047)/1) = Corrected MOA Sight Adjustment

((((Bullet Drop (+) * (1.0 - cosine of angle)) + Bullet Path) / ((Range/100)*1.047)/.955) = Corrected IPHY Sight Adjustment

Cheers,

Doc
 
#16
Re: On the fly Uphill & Downhill shot formulas

I'll have to mess with the Sierra method on paper quite a bit, the improved riflemen formula I'll give a shot. It will be interesting to do the LOS/HR method then compare it to the improved riflemen rule method.
 
#17
Re: On the fly Uphill & Downhill shot formulas

I have a slope doper when I have time to look at my data book and adjust for the shot if I am hunting and and my game surprises me I just hold low like other's have said .

You will learn a lot just buy going and shooting at angles , but I do recommend the slope doper .

Dave .
 
#20
Re: On the fly Uphill & Downhill (A.S.L.I. device)

The best device I've seen for computing hold-under for uphill & downhill shots is the Horus Angle Slope Level Indicator (ASLI) that attatches directly to your scope or rail.

It's dial shows <span style="font-style: italic">two</span> scales:
Outer Ring is calibrated in Cosign
Inner Ring is calibrated in Degrees

Above the dial is a cant level.

This is a very compact,inexpensive (about $70.) but fool-proof item. It can be mounted on scopes (30 mm & 34 mm) left or right side or directly on a Picatinny rail, depending on the mounting bracket you want.
 
#22
Re: On the fly Uphill & Downhill (A.S.L.I. device)

I just go dork and use the "Strelok" app on Droid. So far it works like a charm and it's fun to play with during slow business power points.
 
#23
Re: On the fly Uphill & Downhill shot formulas

We still have buildings in Florida
smile.gif


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Chiller</div><div class="ubbcode-body">

the larger question is where are you going to need this in FL...???...??? </div></div>
 
#24
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jAXDIALATION</div><div class="ubbcode-body">We still have buildings in Florida
smile.gif


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Chiller</div><div class="ubbcode-body">

the larger question is where are you going to need this in FL...???...??? </div></div> </div></div>

For starters!!!
 
#25
Re: On the fly Uphill & Downhill shot formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Hold low... at the pelvis is the quick and dirty field expedient way to do it.

also I posted an intro lesson to angles & altitude in the Online Training Section </div></div>

+1.

This is the quick and hasty method we used when i was in. If your setup in a position for and extended period of time then you can run all your formulas to get it gnats ass, but more often then not that will not be the situation, so we just used to tell them to shoot the in the groin. I mean hell, the worst that could happen is you actually shoot them in the dick. Wouldnt that be some PsyOps stuff. I can hear the enemy now............... " the Americans have Snipers out there that are shooting us in the dick!..........I didn't sign up for this! I'm outa here!" LMAO! That's good stuff right there!
 
#27
#28
Lots of good advise. One I haven't seen is using a map.

If you're good with a map, you can use it and a protractor to get the flat line range. A gps will do the same thing. When I teach LE Sniper classes I have people get a plot map of the city from the city engineers, like the map, it will give you the flat line distance, from lets say the third story of a building to the ground floor of the one across the street.
 
#37
an ACI is a simple and easy way to get it done if you don't know traditional methods or how to use a slope doper. Just aim at the target and look at the dial on the ACI for the proper cosine, then multiply that by your distance and you're set.

just remember, you change your elevation to adjust for the angle, but you still adjust your wind for the total range as the bullet is still traveling that far.

Example: you're shooting at a target 400yds away down a 40deg angle. The proper cosine for this is .77 so 400 x .77 is 308. you adjust elevation for 308 but still adjust wind at 400yds.
 
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