Foretrex 701 not calculating zero offset?

[skierhs]

So I was at the range today and kept shooting low. I was using the 701 which was giving me a firing solution of 11.5 Moa (IK, IK moa but its what my camp communicates in). Once I was home I ran AB off of my computer and I am getting a very different solution. My computer is telling me I need 14.97 Moa for 600 yards. My 701 is claiming 11.62 Moa needed. Can anyone else replicate this same issue? Once Thing is that I am using a zero offset for different bullets. The off set for this load is -1.75 inches zero height and -1.26 inches Zero offset. I have spin drift, coriolis, and aerodynamic jump set off on the 701.

My atmospherics are
Temp: 24f
Preasure: 26.66 hg
Humidity: 50%
Lat: 46.9

Gun properties
Bullet: RUAG Swissp
Velovity: 2608 fps
Zero: 100 yards
Seight height: 2.31 in
Twist rate: 10 twist

 

[skierhs]

 

[skierhs]

Update: I ran my berger 300gr hunting load that has no offset and the programs match up perfectly.

 

[DocUSMCRetired]

Is your FW up to date on the Garmin 701? It should be Version 3.2.

 

[skierhs]

Yes it is v3.20

 

[DocUSMCRetired]

Did you build the profile on the Garmin? Or using software and transfering it over? If it was a transfer, go into the profile and double check the data went over.

 

[skierhs]

They Look to be the exact same from my profile loader. I did not build it in custom on the device.

 

[DocUSMCRetired]

I meant on the Garmin 701 itself.

 

[skierhs]

I meant on the Garmin 701 itself.

Gotcha, yes the garmin is showing the same data as shown in the screen shots.

 

[skierhs]

I meant on the Garmin 701 itself.

If it matters, I was using the range card on the foretrex when i was finding the error.

 

[aaronk]

Yes, I ran into the same issue. https://www.snipershide.com/shooting/threads/foretrex-701-zero-height-offset-backwards.6918939/

The problem is the zero offset is BACKWARDS in the 701. If your zero offset is high, you actually need to input it as a NEGATIVE number, instead of positive, to get the correct dope. The same is true with the left and right offset. Seems to be a bug in the software as the manual tells you to input the values like you would any other zero offset in any other calculator.

This confused the heck out of me when I first used my Foretrex as well.

 

[skierhs]

Yes, I ran into the same issue. https://www.snipershide.com/shooting/threads/foretrex-701-zero-height-offset-backwards.6918939/

The problem is the zero offset is BACKWARDS in the 701. If your zero offset is high, you actually need to input it as a NEGATIVE number, instead of positive, to get the correct dope. The same is true with the left and right offset. Seems to be a bug in the software as the manual tells you to input the values like you would any other zero offset in any other calculator.

This confused the heck out of me when I first used my Foretrex as well.

Thats one of the wierdest things ive seen. Sure enough, I ran it on my desktop and the solution was wrong, i ran it on the foretrex and the solution was right. So now i have two profiles with the opposite off sets yet it lines up on the range card perfectly. Thank you for your help!

@DocUSMCRetired There you go, not sure why its reversed in the foretrex but its all working now.

 

[skierhs]

The only thing other thing to keep in mind now is the wind hold is as if the wind was comming from the oposite dirreciton.

edit- I kept the horizontal offset as negative and switched the vertical offset to posotive and now its all lined up perfectly.

 

[aaronk]

The only thing other thing to keep in mind now is the wind hold is as if the wind was comming from the oposite dirreciton.

edit- I kept the horizontal offset as negative and switched the vertical offset to posotive and now its all lined up perfectly.

You can switch around your horizontal (windage) offset as well so you don't have to manually calculate anything windage wise.

 

[skierhs]

You can switch around your horizontal (windage) offset as well so you don't have to manually calculate anything windage wise.

Yeah, that’s exactly what I ended up doing, hence my edit haha

 

[DocUSMCRetired]

Thats one of the wierdest things ive seen. Sure enough, I ran it on my desktop and the solution was wrong, i ran it on the foretrex and the solution was right. So now i have two profiles with the opposite off sets yet it lines up on the range card perfectly. Thank you for your help!

@DocUSMCRetired There you go, not sure why its reversed in the foretrex but its all working now.

I will need to ask Garmin.

 

[stellan0r]

I did also run into a problem with values not matching (compared to Strelok Pro) and in my case setting "Aerodynamic Jump" to off resulted in matching values - seems like Strelok does not suppoert Aerodynamic Jump option (in my case it resulted in 0.12 mil error - not much to be honest, but still

 

[skierhs]

I did also run into a problem with values not matching (compared to Strelok Pro) and in my case setting "Aerodynamic Jump" to off resulted in matching values - seems like Strelok does not suppoert Aerodynamic Jump option (in my case it resulted in 0.12 mil error - not much to be honest, but still

Much appreciated but it was off already.

 

[Darkhorse1]

Yeah, that’s exactly what I ended up doing, hence my edit haha

So if you left the offset negative, didn't that mess up the 100yd zero for that load, or are you just concerned with the elevation being on and holding accordingly at distance for wind not worrying about the 100yd zero? I just got one of these, and this piece is tripping my up a little since it's opposite from my Ballistic AE app on my phone.

 

[skierhs]

So if you left the offset negative, didn't that mess up the 100yd zero for that load, or are you just concerned with the elevation being on and holding accordingly at distance for wind not worrying about the 100yd zero? I just got one of these, and this piece is tripping my up a little since it's opposite from my Ballistic AE app on my phone.

I have to think about this, haven’t been shooting in a little while and so I’m not sure what I’m doing haha

 

[Darkhorse1]

I have to think about this, haven’t been shooting in a little while and so I’m not sure what I’m doing haha

ha! Yeah, my thinking is that in a hypothetical situation of zero wind...you could dial accurately for elevation at any distance but would be off target horizontally by x doing it your way, whereas if you had used the input, would be dead on at any distance. Obviously in real world elements, that's not the case, so would probably just need to adjust hold for wind after first shot (but slightly more since you didn't account for it). That seems to make sense in my mouse brain, but not sure lol. I've got a ticket in with Garmin to just fix the software so it matches everything else which seemingly would be an easy code fix. Just make negative positive, and push an update.