Hard Sums!

[jcampbellsmith]

Yes JCS, sorry, got my numbers a little back to front... I'm juggling a baby, Frozen on the TV at full belt and trying to do math! :-/

 

One thing I'm now not sure on... If I am to enter my range in to Strelok, do I give my horizontal range of 1000 yards or my actual range of 1013 yards?

Thanks. I don't know Strelok, but AB gives both options for range. I get horizontal range from my binocs so I don't bother entering up or down angles in the ballistics app. Regards JCS

[The_Dogge]

Thanks. I don't know Strelok, but AB gives both options for range. I get horizontal range from my binocs so I don't bother entering up or down angles in the ballistics app. Regards JCS

 

Using horizontal range is a pretty rough approximation, you would get a more accurate solution by using the proper range (line of sight) and entering the angle in the ballistic app.

I don't know about AB but Strelok uses (or can use) the camera to input the angle.

[jay666d]

Thanks for all the input guys...

 

I understand everything that has been said, and the math involved, I guess I've just been mixed up on wether to input the line of sight distance or the horizontal distance. (Something I will look into for my app!)

 

I've also just looked at my RF (and its instructions) and it turns out that it automatically calculates and gives me the horizontal distance!

 

As for doing the math, I will carry on to do it the long way, not only because I like it, but because now that I'm using the GPS I still need to be able to work out my angle.

 

I suppose I don't need to find the hypotenuse (line of sight) because I'll have at least 3 values to work from. (90 degree angle, horizontal distance, elevation difference)

[jay666d]

1000 yrds flat dial for 1000yrds

1000 yrds from a 10 degree vantage point, actual range is 1013 yards...

If the app has the ability to calculate the drop including an angle, then you can enter all the information as you have it...

If not and you have to compensate, dial for 1008 yrds... (This is spesific for my bullets and data!)

Now that I've put the child down and can concentrate on the math, I must correct what I said.

 

Now knowing also that I must go off the horizontal range and not the line of sight. For my bullet I must dial in for 995 yards!

[jay666d]

Just had confirmation from Igor at Strelok, for his app you input the actual line of sight distance and the slope angle.

[Dalua]

This is what experienced ghillies have advised long before ballistic apps: "On a slope,don't hold so high",and failure to take this advice can be rebuked "Wasted into the bl**dy heather"....and for especially poor shots...."somewhere in Scotland". :-)

 

In my experience, Highland stalkers don't need ballistic apps because they're close enough not to.

The rule of thumb that for a given range 'uphill, hold low: downhill, hold lower' should do fine as long as you bear in mind that deer have three dimensions.

 

Do it properly and the stalker will be pleased, and the ghillie (if there actually is one) will bring the pony (or quad) along shortly.

[That bald headed Geordie]

Grrrrrrrrrrrrrrrrrrrr!!!!!

 

Please guys use MATHS and not bloody MATH!

We are not in America! Have a nice day

[tackb]

Have you sent it yet...........

[gbal]

In my experience, Highland stalkers don't need ballistic apps because they're close enough not to.

The rule of thumb that for a given range 'uphill, hold low: downhill, hold lower' should do fine as long as you bear in mind that deer have three dimensions.

 

Do it properly and the stalker will be pleased, and the ghillie (if there actually is one) will bring the pony (or quad) along shortly.

It is of course vague,and wrong.

The pragmatic advice-given it's a shot beyond the zero-is 'hold on inch or two lower than you think the distance needs" -uphill or down.ie allow a couple of inches less drop adjustment.

With a rifle zeroed at 100y,and a heart shot at a 275 stag,"holding low" risks a miss under the beast.

I agree that the relatively short range-and therefore small effect of slope-makes any adjustment much less important-and with a 200 zero is perhaps best not mentioned.

You DO NOT aim low by some unspecified amount (a recipe for a miss)- BUT you do not allow so much drop adjustment for the distance,whether up or down.

Otherwise you had best have some big stags,then erroneous advice might sometimes succeed

despite itself.

 

"Allow an inch or two less elevation adjustment than you would on the flat".

 

Anything else is just plain wrong/confused-practically and theoretically-perhaps why this topic is quite simple but gets pretty muddled up....or down!

 

gbal

[tackb]

if your gong was fixed to a glacier it's probably moved out of range by now !

 

just get it shot already !

[gbal]

if your gong was fixed to a glacier it's probably moved out of range by now !

 

just get it shot already !

Good advice.But for the afficionados,there is a formula for laminar dynamic flow,which will allow the actual distance the glacier has moved .All you need feed in is the weight of the ice,it's core temperture,the relative gradient of irregularity of the substratum,and a few more vector transformed variables,which come more or less as standard on the Alpine Special Kestrel which you set by a GPS system,and calibrate according to the SchweisserGestellingBrachtdata-available from the Swiss Alpine Society,though not in English. Then just multiply the figure -if it isn't 00000015mm,you have probably made a mistake- by the time elapsed since you started the calculation ,and that's your shooting solution,well once you have allowed for earth's rotation-use the N Hemisphere-and ignore the sharp rise in the Swiss Franc.You can,for simplicity,also ignore the rise in elevation of the Northern Hemisphere due to tectonic drift this millenium.

 

Or just give it .98789327 % less elevation than the number your range data suggested when you first looked it up,before this thread.

 

gbal

[gbal]

if your gong was fixed to a glacier it's probably moved out of range by now !

 

just get it shot already !

Good advice.But for the afficionados,there is a formula for laminar dynamic flow,which will allow the actual distance the glacier has moved .All you need feed in is the weight of the ice,it's core temperture,the relative gradient of irregularity of the substratum,and a few more vector transformed variables,which come more or less as standard on the Alpine Special Kestrel which you set by a GPS system,and calibrate according to the SchweisserGestellingBrachtdata-available from the Swiss Alpine Society,though not in English. Then just multiply the figure -if it isn't 00000015mm,you have probably made a mistake- by the time elapsed since you started the calculation ,and that's your shooting solution,well once you have allowed for earth's rotation-use the N Hemisphere-and ignore the sharp rise in the Swiss Franc.You can,for simplicity,also ignore the rise in elevation of the Northern Hemisphere due to tectonic drift this millenium.

 

Or just give it .98789327 % less elevation than the number your range data suggested when you first looked it up,before this thread.

 

gbal

Grrrrrrrrrrrrrrrrrrrr!!!!!

 

Please guys use MATHS and not bloody MATH!

We are not in America! Have a nice day

Grrrrrrrrrrrrrrrrrrrr!!!!!

 

Please guys use MATHS and not bloody MATH! :mad:n

We are not in America! Have a nice day

Trigonometry is only one of the mathematics.

 

:-) g

[Brummy Mark]

Your gps well may be wrong for the distance most of the time, floating signal, easy way to check, put it at your cross hill shooting point and leave it there for a few hours, then upload the track log to see where it has been, you might be surprised to see that it moved up to 250m in random patterns as it lost satelites and the signal bounced around etc etc., that certainly wont help.

Get a 1:25000 OS map of your area and work it all out from that.

[gbal]

Your gps well may be wrong for the distance most of the time, floating signal, easy way to check, put it at your cross hill shooting point and leave it there for a few hours, then upload the track log to see where it has been, you might be surprised to see that it moved up to 250m in random patterns as it lost satelites and the signal bounced around etc etc., that certainly wont help.

Get a 1:25000 OS map of your area and work it all out from that.

Complex ,no?

 

If you are lucky,your deer may have wandered around randomly too,but come back to square one,within 300 yards of you.

 

Hold one and a half inches lower than you would on the flat and shoot.

 

gbal

 

ps:that's the number we first thought of,and it works.

[jay666d]

Your gps well may be wrong for the distance most of the time, floating signal, easy way to check, put it at your cross hill shooting point and leave it there for a few hours, then upload the track log to see where it has been, you might be surprised to see that it moved up to 250m in random patterns as it lost satelites and the signal bounced around etc etc., that certainly wont help.

Get a 1:25000 OS map of your area and work it all out from that.

 

 

Cheers Mark,

 

You make an excellent point... Something which I will test.

 

You'll be pleased to hear, I have been using an OS map to confirm my distance.

 

Gbal & everyone else who has mentioned moving quarry and the time it would take to make these calculations... I'm shooting steel! Please stay on topic!

[gbal]

Touche,Jay.

Are you allowing for cosmic variation in the local magnetic fields?

 

The more serious point,though,is that almost all measures are subject to error,and often only approximate corrections-if that-can be applied.Often we are 'unaware' of the 'errors'-it's just a miss!

(atomic clocks are phenomenally accurate-but have to be reset 'periodically' because the earth's rotation is very slightly skewed-not an everyday concern for most of us.)

 

That's why it can get to be seriously........err "Hard sums" !

 

But moa+ targets will exceed most of the vey fine tuning error,and misses will be for rather gross errors-like range/wind misjudgements.

 

gbal