Anyone familiar with Atrag program??

[subseauk]

Hi all
I been given a Kestrel windmeter with the built in Horus Atrag system to play with.

Not having used the Horus software before i am fumbling a little and could use some input from the more experienced users.

I have been provided with what i believe is 168grain .308 / 7.62 Winchester ammo which is producing about 2894fps average over 10 rounds. I have no provided BC but am using .472 on a suggestion ( no idea where it came from).

Zeroing at 100yds the Horus system predicts elevation ( 0.1 click milrad turrets) needed at
200yds at 0.61 ( i used 0.9 )
300yds at 1.45 ( i used 1.0 )
400yds at 2.4 ( i used 2.1 )
1000yds at 11.77 ( i used 11.1 )

A quick read of the limited user manual supplied talks about true drop and i thought this meant you could enter in actual values used and increase the accuracy of the predicted bullet drop but it does not seem to allow changes to the click values used only BC, MV and something else.

Can anyone steer me right on how to get the best setup on this Kestrel unit and if it is possible to increase the predicted accuracy by inputting values actually used on the range etc.

Any help appreciated.

Best Rgds
Kev

 

[Chiller]

Re: Anyone familiar with Atrag program??

http://www.nkhome.com/support/pdfs.html

 

[RG in Idaho]

Re: Anyone familiar with Atrag program??

You alter the BC or MV until the dope matches what you observed in the field.

It would be best if you knew either the actual BC or MV. That way you are only adjusting the unknown variable.

 

[subseauk]

Re: Anyone familiar with Atrag program??

Hi RG

I have chronographed the MV and the got average as 2894fps over 10 shots
( 2773 to 3172fps )
So are you saying to just adjust the MV input until Drop matches what i encountered on range?
Seems strange they dont allow you to input the actual Drop and work from that but i guess that would mean a lot more internal calculations or something.

Appreciate the input.
Rgds
Kev

 

[subseauk]

Re: Anyone familiar with Atrag program??

Hi Chiller
This was the manual i am using but it is not really clear, ( to me anyway ), as to how to input the actual drop or clicks used instead of predicted ones.
The info from RG clarifies it a bit but it seems weird that you have to adjust a known value such as MV done by chrony rather than just input the true clicks used. Perhaps something that Horus could look at.
The other real dissapointing thing about the combined unit is that you cannot output/print a range card even though there is an interface to a pc.

cheers
Kev

 

[RG in Idaho]

Re: Anyone familiar with Atrag program??

In the True Drop menu:

Since you have the actual MV; adjust the BC until the drop on the unit matches what you observed in the field.

 

[subseauk]

Re: Anyone familiar with Atrag program??

Thanks RG

Will let you know how it goes

Best Rgds
Kev

 

[subseauk]

Re: Anyone familiar with Atrag program??

RG
I have gone into the TD menu and adjusted the BC value downwards until the click value matches the amount used on the range at 1000yds.
However when i go back to the range card display the values shown at 1000yds do not match those shown in the TD menu when adjusting the BC??
Any ideas?

I have set all the enviromental values to those recorded on the day of the shoot incase the current pressure etc affects the calculations.

If it is any help i could email all the data i have for the day on the range etc for you to have a look at ( if you have time etc ).

rgds
Kev

 

[RG in Idaho]

Re: Anyone familiar with Atrag program??

I don't know much more about the unit than you do. I'm just an end user.

The person you that can probably help is Ben Neilsen(sp)at Kestrel. He is their support person for the unit. He was very helpfull when I contacted him.

 

[subseauk]

Re: Anyone familiar with Atrag program??

Thanks

i'll drop him a line.

Rgds
Kev

 

[marku]

Re: Anyone familiar with Atrag program??

I dont think you should have that much variation in muzzle velocity? I would check the chrono and try it again.

 

[Geronimo]

Re: Anyone familiar with Atrag program??

The mv variation is ten times my variation in my ammo, tha's not helping at all.

 

[Speeddog]

Re: Anyone familiar with Atrag program??

OP: Liindy often references an excellent article on causes of errors in ballistic programs. You can search on his name or on the reference.

Will be worth the read and it should help a lot in figuring out where to go from here. The short form is to be sure your BC and environtal variables are as accurate as you can get them. Then zero at 100, walk your distances from there, take careful note on where your actual POIs are, adjust your entered MV until the program's prediction exactly fits your observed data. You should get your observed MV as close to true as you can; it'll save time and lots of frustration.

Good luck. Hope this helps.

 

[subseauk]

Re: Anyone familiar with Atrag program??

Hi Guys
I am trying to get a BC from Winchester ( who apparently made the ammo ...says winchester 168grain on box!! ). The ammo is being provided by rifle company and was bought as a bulk purchase (no further info).
The MVs of 10 rounds were measured and all seemed to log ok at time.
Even with the variations in MV the POI elevation wise remained within an inch or two at 1000yds.
The environmental data was logged at time of zero and on the 2,3,4,900 and 1000yd targets ( all on same day as well ) only thing changed slightly was wind which went up a little at times from 5-7mph.
I have tried altering the BC in True Drop but when doing so the elevation setting matched in this menu but going back to the range card it does'nt and all the other range drops dont match.
all a bit confusing.

Woud any Kestrel / Horus owners be willing to enter in my data and see what they come up with? I can email ammo, rifle, zero, enviromental and range data.

I have a call in to Kestrel and waiting a reply.

Cheers
Kev

 

[Lowlight]

Re: Anyone familiar with Atrag program??

try .452 for BC

FYI, none of these software solutions are 100% for every rifle, there are too many variables for the programs to work with.

You can get "close" and each person's definition of close is different, but getting exact everytime is rare at best.

 

[subseauk]

Re: Anyone familiar with Atrag program??

Thanks Lowlight

Just to point out that the Kestrel /Horus unit does not seem to be the same program as Horus on its' own and certainly not as user friendly if you are not familiar with it.

I remember seeing somewhere a program where the BC could be adjusted at various ranges. This would seem to be a better method as the drop curve could be tweaked at each distance! Can Horus do this?

Cheers for the feedback guys.

 

[Lowlight]

Re: Anyone familiar with Atrag program??

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

Just to point out that the Kestrel /Horus unit does not seem to be the same program as Horus on its' own and certainly not as user friendly if you are not familiar with it.

I remember seeing somewhere a program where the BC could be adjusted at various ranges. This would seem to be a better method as the drop curve could be tweaked at each distance! Can Horus do this?

Cheers for the feedback guys.</div></div>

Well, no, they can't do that, it is just like the 5.11 watch, that has a Horus ballistic engine in it, and doesn't work the same. It's a slimmed down version as with the watch the kestrel doesn;t have as much computing power as a dedicated PDA so you get what they can give you, which is not very much.

 

[RG in Idaho]

Re: Anyone familiar with Atrag program??

<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: subseauk</div><div class="ubbcode-body">Thanks Lowlight

Just to point out that the Kestrel /Horus unit does not seem to be the same program as Horus on its' own and certainly not as user friendly if you are not familiar with it.

I remember seeing somewhere a program where the BC could be adjusted at various ranges. This would seem to be a better method as the drop curve could be tweaked at each distance! Can Horus do this?

Cheers for the feedback guys.</div></div>

Well, no, they can't do that, it is just like the 5.11 watch, that has a Horus ballistic engine in it, and doesn't work the same. It's a slimmed down version as with the watch the kestrel doesn;t have as much computing power as a dedicated PDA so you get what they can give you, which is not very much. </div></div>


The Kestrel w/Horus does allow the BC to be adjusted based on range. The entries go into a BC distribution table. Multiple muzzle velocities based on temperature can also be put into a MV table. The program extrapolates between BC's and velocities based on Temp and range. I know that the mv/temp is a linear extrapolation. I don't know about the usage/methodology for multiple BC's.

I did find out that entering multiple BC's and MV's in tables over rides the ability to adjust the data via the True Drop feature.

 

[bowhuntr09]

Re: Anyone familiar with Atrag program??

I don't have one and never used one, but there seems to be a lot of good info in its use in this youtube series.

[video:youtube]http://youtu.be/pg6oqT5jVds[/video]