Angle drop chart??

[KMD]

Shot to 700 over the weekend, set steel up @ 8° incline. Input 1600-b ranged yardage into Ballistic AE with no compensation for angle. First round hit was dead center elevation, as well as subsequent shots. Leads me to confirm/conclude that my unit is giving me trued distance to target. I seem to recall engaging EHr on initial setup, but skipping over the ballistic stuff.
Sorry, don't have any steeper country to test in, but my system ain't broke, so I ain't gonna mess around with it and potentially screw up a good thing.
If I were shooting in steep mountain country, I'd invest in an cosine ACI, and run the 1600-b with everything turned off, using LOS distance, and let the ballisitc program do its job...

 

[LaHunter]

If it works, stay with it.
Cosine of 8 degrees is .99, so (.99)(700 yards)=693 yards corrected yardage. Not enough angle to determine if the range finder is calculating the line of sight angle or not. Very nice shooting at 700 yards however!

 

[BillyGoatGruff]

Shot to 700 over the weekend, set steel up @ 8° incline. Input 1600-b ranged yardage into Ballistic AE with no compensation for angle. First round hit was dead center elevation, as well as subsequent shots. Leads me to confirm/conclude that my unit is giving me trued distance to target. I seem to recall engaging EHr on initial setup, but skipping over the ballistic stuff.
Sorry, don't have any steeper country to test in, but my system ain't broke, so I ain't gonna mess around with it and potentially screw up a good thing.
If I were shooting in steep mountain country, I'd invest in an cosine ACI, and run the 1600-b with everything turned off, using LOS distance, and let the ballisitc program do its job...

I agree, Don't mess with it. Did you try to push the secondary button twice real fast? It should display your settings? In order for me to get into the menu, I have to hold the secondary button for 2+ sec. so if you hit hit fast you shouldn't change any settings.

 

[BillyGoatGruff]

So I went out and did a little testing this weekend too.
On Saturday I went out to my Mom's nice flat 1200 acres and got some drop data to validate my trajectory. That all went pretty well (I think)
checked my 200 yd zero. Then went out to 585 and then to 823. first solution called for 8 moa and hit 1 moa low. Went up to 9 moa and shot another group and was good to go.
second solution called for 13.75 moa. That one hit 2 moa low. made that corection and was good to go on that second group. Put that info into the G7 program and it adjusted my velocity about 14 fps. Now if I input those same distances at that elevation I get 9 moa and 15.9. So I think that went good.

So Sunday I went and did a little angle shooting. It's extremely difficult to find a spot to get real steep shots. I know of a little peak that I could go too and find at least something.
I set out 4 one gallon jugs for my targets planning to find four shooting positions. Its a very rocky peak.Lots of big boulders to shoot from.
First setup, 310yd line of sight and 22 deg according to the 1600B. Fyi it was very windy. I had a pretty constant 8-12mph wind at the targets pretty close to 90 deg to the shooting location. Up at my shooting position the wind was all over the place. sometimes from the side, sometimes from behind going down and sometimes coming up. I pretty much gave up trying to dope it up where I was and just figured a 10mph cross wind at the target.

I don't shoot a muzzle brake so the only way I can see the impact at the target was to video through my spotting scope.
So I input all my peramiters. I was able to get a station pressure through my shooter app on my phone. I got the angle from the 1600B.
Solution called for a up 1.7 moa I held for about a 1 moa wind. Fyi, a flat 0 deg solution calls for 2.2 moa.

First shot went right over the jug. About an inch after viewing the video. Second shot same result. Third shot looked like it went through the opening in the handle.
All three were just a tad high, about one moa from aiming point I was a little frustrated. I returned the scope to zero and hit the target about 2" from the bottom.

I stopped my shooting there. The wind was getting crazy and I new it would get worse the higher on the mountain I went.

So I'm a little frustrated. I'm not sure if my angle data is flawed or if my drop data is? or if the 1600b's angle reading is off?

My other thought is if the wind could have pushed the bullet up? This peak is kinda like a pyramid and the wind at the target was coming up the draw from the right and crossing the saddle where the targets were.

I plan to go again in a couple weeks and hope it's not so windy.
I know it's a small sample and not really a long shot. My plan was to hit like something in the 300,400, and 500 yd ranges.
The next time I go I think I can get close to 30deg at the 500 yd range

Any thoughts???

BGG

 

[KMD]

If it works, stay with it.
Cosine of 8 degrees is .99, so (.99)(700 yards)=693 yards corrected yardage. Not enough angle to determine if the range finder is calculating the line of sight angle or not. Very nice shooting at 700 yards however!

Thanks for that, and thank you for making mention of what I'm beginning to suspect myself! It is entirely likely that my 1600-b isn't actually correcting for anything, and I'd just convinced myself that it was, LOL!

Need to add, that when shooting beyond 900yds, I always add shooting angle into my ballistic solver. For one, that is beyond the distance of the Leica 1600-b capability to angle compensate (875yds max). Secondly, at that increased distance, a deviation of a only few degrees can compound enough to create a noticeable POI shift on target.



OP, for steep angle, short range shooting, don't overthink it! Those kinds of shots are alot more easy to figure, without the need for fancy gadgetry. ~300yds, your dealing in a few inches of deviation, at most. Generally speaking, the steeper the angle, the lower you need to hold...

 

[LaHunter]

I would establish my drop charts by actually shooting groups at known distances at known elevation / temp. Sounds like you have done that. I have mine verified in 100 yard increments. The only thing I use my Ballistic App for is to just get a starting point for moa adjustment to get me close, but it is seldom exactly spot on. I will also use my Ballistic App to help me make a drop chart for an elevation that is extremely different from where I live and shoot. I live at 100 ft above sea level and hunt as high as 8,000 ft above sea level.
My opinion is there are too many variables that have to be exactly accurate for the program to be totally accurate. Disclaimer: I am no where close to being as knowledgeable or as skilled as some of the other members on this forum.

Next I have a laminated card with angle cosine values on it in 5 degree increments: 10* cosine=.98, 15* cosine=.97, 20* cosine=.94, 25* cosine=.91, etc. These values can be looked up with a google search. The cosine value of a given angle is always the same.
Once you know the distance and the angle, it is simple math to just multiply the cosine value by the yardage to get the corrected 'shoot to' distance, as long as you are taking elevation, and maybe temp into account. This is what I use to try to keep it simple and eliminate the need for a shooting program during a hunting situation.

Hope this makes sense and is of use.

 

[BillyGoatGruff]

I would establish my drop charts by actually shooting groups at known distances at known elevation / temp. Sounds like you have done that. I have mine verified in 100 yard increments. The only thing I use my Ballistic App for is to just get a starting point for moa adjustment to get me close, but it is seldom exactly spot on. I will also use my Ballistic App to help me make a drop chart for an elevation that is extremely different from where I live and shoot. I live at 100 ft above sea level and hunt as high as 8,000 ft above sea level.
My opinion is there are too many variables that have to be exactly accurate for the program to be totally accurate. Disclaimer: I am no where close to being as knowledgeable or as skilled as some of the other members on this forum.

Next I have a laminated card with angle cosine values on it in 5 degree increments: 10* cosine=.98, 15* cosine=.97, 20* cosine=.94, 25* cosine=.91, etc. These values can be looked up with a google search. The cosine value of a given angle is always the same.
Once you know the distance and the angle, it is simple math to just multiply the cosine value by the yardage to get the corrected 'shoot to' distance, as long as you are taking elevation, and maybe temp into account. This is what I use to try to keep it simple and eliminate the need for a shooting program during a hunting situation.

Hope this makes sense and is of use.

Thanks LaHunter,

I think I'm going to do exactly what to said. Make a chart with the cosine's for a list of angles.
I'm pretty sure my data is good though. If I do the cosine of 22 deg that gives me a corrected distance of 285. if I pump in 285 for zero deg it gives me the same correction of up 1.7 moa as I got for the angle solution.

I'm pretty sure it was the way the wind was blowing from below me. I think even though I thought it was 90 deg to my firing position. I think the wind was coming more from under me and pushed the poi up?
Only way to be sure is to go test again. I'll do that in a couple weeks.

I'm going goat scouting this weekend and I'm going to take my range finder and do some ranging to see what type of angles I might run into.

BGG

 

[BillyGoatGruff]

I'm toying around with the idea of getting a new wind meter that can give me altitude and pressure vs using my gps. weatherhawk sm28 sky master? anyone have experience with these?

BGG

 

[KMD]

This is the treestand bowhunter in me coming out, but a quick way to swag a 25° correction is, as follows:

Ranged distance is 480 yds
Since cosine for 25° is .91, that's close enough to 90% of ranged distance for swag purposes.
To solve for that, do math on the fly...
Simply knock the last digit off ranged distance, leaving 48, which is 10% of 480
Then, subtract 480-48 to get the 90% value

Corrected range =432

It ain't perfect, but darn close...

 

[BillyGoatGruff]

This is the treestand bowhunter in me coming out, but a quick way to swag a 25° correction is, as follows:

Ranged distance is 480 yds
Since cosine for 25° is .91, that's close enough to 90% of ranged distance for swag purposes.
To solve for that, do math on the fly...
Simply knock the last digit off ranged distance, leaving 48, which is 10% of 480
Then, subtract 480-48 to get the 90% value

Corrected range =432

It ain't perfect, but darn close...

Thanks KMD,
I'll try to remember that. Good info.

BGG

 

[BillyGoatGruff]

Any opinions on wind meters?

I'm looking at these two.

weatherhawk sm28 sky master or a Kestrel 2500?

I think all I really want it to do along with the standard temp and wind is the ability to get a pressure reading/altitude?

Thoughts/opinions?

BGG

 

[mtnclimber]

The ADC pro has worked well for me. its at B&H photo for $110 right now.

 

[BillyGoatGruff]

The ADC pro has worked well for me. its at B&H photo for $110 right now.

That has a lot of features. has it proven to be pretty accurate for you?

BGG

 

[KMD]

Thanks KMD,
I'll try to remember that. Good info.

BGG

One more thing!
If you want to actually use cosine compensation math at distance, you'll want to apply the cosine % to the DOPE, not the YARDAGE
Same math applies, but I'd highly recommend entering that info into your ballistic solver and let it do the work...

 

[Broz]

Any opinions on wind meters?

I'm looking at these two.

weatherhawk sm28 sky master or a Kestrel 2500?

I think all I really want it to do along with the standard temp and wind is the ability to get a pressure reading/altitude?

Thoughts/opinions?

BGG

My Kestrel 2500 NV has been a great unit. I have used it so long and so much It looks like it has been drug behind the truck. I have worn the wind impeller out to the point it fell apart once. I called Kestrel and they sold me a replacement that changes out easily. The 2500 will give everything you need for a ballistic solution except humidity. I estimate humidity from what it has been averaging. Humidity makes the least effect to your solution. You can run a solution with 20% to 80% and it will be the same in dial up. And, of course the 2500 does not give azmuth for use with coriolis. You would need to get that from your phone app or carry a small compass like I do. The 2500 does give temp. Baro psi, altitude, wind speed, average wind speed and max wind speed and maybe a couple more I don't use and cant think of off hand. All in all I have found the 2500 to be a great value and has served me well.

Jeff

 

[BillyGoatGruff]

One more thing!
If you want to actually use cosine compensation math at distance, you'll want to apply the cosine % to the DOPE, not the YARDAGE
Same math applies, but I'd highly recommend entering that info into your ballistic solver and let it do the work...

Not sure I follow you? I thought the angle cosine % was to get the shoot to range of the line of sight?

BGG

 

[BillyGoatGruff]

My Kestrel 2500 NV has been a great unit. I have used it so long and so much It looks like it has been drug behind the truck. I have worn the wind impeller out to the point it fell apart once. I called Kestrel and they sold me a replacement that changes out easily. The 2500 will give everything you need for a ballistic solution except humidity. I estimate humidity from what it has been averaging. Humidity makes the least effect to your solution. You can run a solution with 20% to 80% and it will be the same in dial up. And, of course the 2500 does not give azmuth for use with coriolis. You would need to get that from your phone app or carry a small compass like I do. The 2500 does give temp. Baro psi, altitude, wind speed, average wind speed and max wind speed and maybe a couple more I don't use and cant think of off hand. All in all I have found the 2500 to be a great value and has served me well.

Jeff

Thanks, Jeff

I'm leaning pretty hard towards the kestrel. It's only $10 more than the sm28 and $20 more than the ADC pro that mtnclimber recommended.
They all seem to be pretty good and have similar features. Kestrel seems to be the most popular.

BGG

 

[KMD]

Not sure I follow you? I thought the angle cosine % was to get the shoot to range of the line of sight?

BGG

What LA hunter referred to, and my intial 'bowhunter math' of multiplying yardage by the angles's cosine, is known as the "rifleman's rule".

What I'm referring to, multiplying the DOPE by the cosine is known as the "improved rifleman's rule".


If you're interested, here's an excellent link that will explain the differences, in painstaking detail:
http://www.exteriorballistics.com/ebexplained/article1.html

Refer to the data tables in the above link, and you'll see the shortcomings of either method, calcualated in % error. The "IRR" is much more accurate, comparatively, to the original "RR" (Table 6, in link), but still provides an unacceptable margin of error at increased distance, and/or angle (Table 7, in link)

So, to make a long story, longer... let your ballistic calculator do the work to solve for steep angle, long distance shooting



As for wind meters, I use a Kestrel 4500 series, for its ability to calculate Density Altitude. Using DA, streamlines the need to measure and input temp, altitude, and pressure independently. In short, its a more simplified (better) 'mousetrap' for quantifying and correcting for, how environmental affect bullet flight.

Good luck & have fun digesting that link!

 

[Ryan Avery]

KMD, why would you put in altitude if you put in pressure?

 

[KMD]

KMD, why would you put in altitude if you put in pressure?

I wouldn't and I don't, Ryan. Just made it known that I use DA which covers all the bases, in one measured data point.

EDIT: but to answer your question, I'd input station pressure at shooting location, with altitude set to "0". Technically, you'd still have to enter the "0 ft" as altitude in the ballistic solver, so that counts as entering data.

Possibly, a more enlightening question, for those unfamiliar with DA, would be:
Why bother measuring and inputting more than one atmospheric condition, if DA accounts for all of them in one simple & easy to digest unit of measure?