Not exactly a flatlander, but the NC Mtns are way taller than those in GA.
Two of my favorite ranges are in Western NC, Dirty John and Panther Top.
Couple of Questions, Dirty John is near the top of a Mtn, guessing 4000ft. Panther Top is much lower in elevation. If I sght in at DJ and move to PT will I be low or high?
Also, how tough is it to get approval from the Freddies to use a range for events such as AS?
I can answer the first question but not the second. For every two thousand feet of change there is a 1 MOA change in your impact. If you are going down the air will be getting denser and thus the bullet will be flying slower and will impact on the target low. For example if DJ is at 4000 feet and you will be shooting at 1500 feet that is a 2500 foot change and therefore a 1.25 MOA change (bullet impacting low). Hope that helps.
That at least explains why after sighting in at Dirty John, I shot low at my first AS.
Well, unless you're shooting a real accurate target rifle (as in a Bench rest, sniper rifle or 1000 yard gun), it isn't going to make much difference. The difference is a matter of air density, which changes day to day as well, not just elevation. The difference is actually with the tolerance of your rifle and ammo, before we get into your hold ability.
There can be a combination of things that compile to cause your bullet to impact lower. For example if you were to drop 3000 feet in elevation (1.5 MOA) and the temperature were to drop 50 degrees (Zeroed in midday at 100 degrees and fired in the morning at just 50 degrees) when you zeroed that would push your bullet down another 2.5 MOA. Plus an altered sight picture may also compile to move your impact. I have no evidence for these numbers but Sgt Craig, AMU service team coach, told me that every 1/16th of an inch of movement resulted in a 1 MOA change in impact. Granted this could all be as a result of NPOA/Sight Picture, ammo change, or any other hardware or software changes. The golden rule is consistency in all aspects of shooting.