Kestrel/Hornady 5700 4 DOF Compass

[Paul1262]

How critical is the DOF and Wind Direction accuracy (+ or - degrees to actual) and is there a way to ensure it's accuracy. I perform the compass calculation by turning the unit periodically however, when I compare what the unit says to a downloaded compass, the results are generally not the same.

 

[azred33]

Since you are using the same compass for DOF and Wind acquisition, the relative headings should be accurate for wind effect on the bullet. DOF on the other hand could be affected depending on how far off the compass is. For a 1000 yd shot with a 6.5 prc you could see 5-10 inches difference if the compass was a full 90 degrees off, but I bet it is more like 15-20 degrees off, so more like 2" off at the worst. Also check if you have your compass set for true or magnetic, that might be some of the variance you see.

 

[Paul1262]

Since you are using the same compass for DOF and Wind acquisition, the relative headings should be accurate for wind effect on the bullet. DOF on the other hand could be affected depending on how far off the compass is. For a 1000 yd shot with a 6.5 prc you could see 5-10 inches difference if the compass was a full 90 degrees off, but I bet it is more like 15-20 degrees off, so more like 2" off at the worst. Also check if you have your compass set for true or magnetic, that might be some of the variance you see.

Really appreciate your reply.

 

[ma smith]

Read this for some background on compass headings

What is declination? | U.S. Geological Survey

At most places on the Earth's surface, the compass doesn't point exactly toward geographic north. The deviation of the compass from true north is an angle called "declination" (or "magnetic declination"). It is a quantity that has been a nuisance to navigators for centuries, especially since it...

www.usgs.gov

 

[Paul1262]

Read this for some background on compass headings

What is declination? | U.S. Geological Survey

At most places on the Earth's surface, the compass doesn't point exactly toward geographic north. The deviation of the compass from true north is an angle called "declination" (or "magnetic declination"). It is a quantity that has been a nuisance to navigators for centuries, especially since it...

www.usgs.gov

Thanks - much appreciated.