BH209/ BDC reticle vs. 7000FT elevation change

[PAhunter58]

Need verification of what I think will happen. Leaving for a NM muzzy hunt soon and have been practicing a good bit at 1200ft elevation. Have a CVA MR 25" Barrel. Shooting 110gr by volume of BH209, pushing a Barnes 290gr TE-Z at 1965ish fps. I am using a NIKON IR BDC. Very accurate out to 300yds.
I am zeroed for 100yds at 1200ft. elev. I am seeing up to a 20 yard difference when I add the 7000ft change in elevation on several of the apps I use.
These happen when you move from one yardage to the next longer one. The delta increases. In my opinion, the difference at 100yds at either elevation would be incremental. So basically I'd like confirmation as to what I am thinking. My crosshairs are 100, I'm at basically at 310 on my 4th BDC circle.

 

[Wapiti1]

Yes, the yardage each circle is accurate for will be farther at 7000ft than at 1200ft.

Keep the crosshair sighted at 100yards, and print out the new chart for 7000ft to use when hunting. When you get to NM, shoot at 100 to check zero, if dead on, you are good to go. You want to maintain a 100yard zero so that your baseline is the same in the ballistics program.

You won't need to re-zero at 7000ft, but should verify. That isn't far enough to show a meaningful difference from the elevation change.

Jeremy

 

[PAhunter58]

Thank you confirming what I was thinking. I certainly intended to re-zero when I got to NM. My only other issue was trusting what I have been reading on what the true ballpark FPS was for my CVA at 110gr by volume.
Very Grateful, Scott

 

[Wapiti1]

If you've shot out to 300yds in PA and the drops were good, then your velocity and BC in the program are also good. The only way to know is to get a solution from the ballistics program, then check it in the real world.

I can say that my Savage ML2 with a 110gr BH209 charge and 300gr Parker w/ sabot shot 1980fps average. I shot drops out to 500yards and calc'ed my BC then used that in the program (Strelok).

Jeremy

 

[PAhunter58]

Shooting again later this morning. Maybe the last time before I head to unit 15 in the Gila. Thanks again for helping me confirm and trust what I am seeing. Have read many of your posts over the years. Glad I got reply's by one of the several veterans on Rokslide, I follow.

 

[SummitsCalling]

100% confirm your zero heading to NM. I always seem to be low there.