How to adjust b.c. to get ballistic chart to match drops


Well-Known Member
May 21, 2011
Southern Arizona
That's assuming the gun is zeroed at 100. Once that is established all the rest of the data should fall in line, but if I have a 500ft elevation 80 F. confirmed zero then go to 9000 ft elevation and 30 F how do I know where to set my zero if I don't actually shoot it.
That’s what the Zero Atmosphere selection is for where you initially zeroed in at.


Official LRH Sponsor
LRH Sponsor
Jun 11, 2010
Ah, so there is that feature. Is this generally accepted to be accurate?
It's worked for me, no matter where I've gone. However, I submit that a 100yd zero with most modern centerfires does not change enough for it to matter.


Well-Known Member
Jan 10, 2013
Meridian, Idaho
Soo... you guys are definetly above my level, thanks for keeping it simple BrentM. I have shot 1,000 yard comp and long range hunt with my father who has kills out to 1,860 yards.
We get close in height from basic charts off of berger website. But wind we usually call the shots left or right and "walk" it in because we usually shoot mountain to mountain with multiply gaps or ravines. I am going to read up on all the extra conditions
Limited on gear backpacking on horses
One of the best things you could ever do is take a LRH hunting class. Generally those types of class focus on things that matter for a hunter. Beyond the basic fundamentals typically the focus is on wind and positional shooting. Wind is almost always the problem for any shooter. With todays tech dialing in elevation is pretty straight forward but reading a ghost across mulitple terrain features is challenging but very doable once you know what to look for and why.

#1. Get an app on your phone and use it. Study it. Really dig into it so it becomes second nature. If there is an area you don't quite understand, study that area. The app is nothing more the combined knowledge and formulas that are put into one place to make life easier on you. Junk in is junk out tho. One thing shooter is not good at is the wind stuff. I don't use it on an app (I have mulitple apps on my phone) so it doesn't matter to me but some programs have a wind segmenting section where you can run scenario's for all sorts of wind changes in speed and direction and see the results. It's very educational and I use for new student instruction. I have multiple apps because often students are all using different platforms.
#2. If you don't have a wind meter or app, you might spring for kestrel 5700 elite with applied ballistics and link. Link is the blue tooth portion that will link it to apps and lrf's etc that are set up with it. For example I use a leica that links to kestrel and will give solutions as far as my lrf will range. Generally my lrf will range to 3200-3500. Some apps, AB for example, also will link with kestrel so you can see results displayed on your phone. One thing about a good meter is that really shows you the changes in the environment while in that environment. Charts printed and taken are not LIVE so you could potentially be limiting to yourself to less accurate data. Mountains can create their own atmosphere so having live and real time data is ultra important to me. Simple density altitude change at 8000-9000 feet can really screw up a guys day if you are not aware of the changes.
#3. Bryan Litz is a good resource for educational books etc. There are segments on the AJ portion, formula y=(.01)(sg)-(.0024)(L)+.032. To understand that formula you need a basic understanding of bullet stability and where that comes from. The apps will show you stability, such as the berger twist rate calculator etc. There are short cuts that require very little math for AJ and wind. At any rate the chapter in his book gives you in depth understanding on why and what affect left to right vs right to left wind has on the vertical wind component. Google video's are fun to watch as they illustrate the process.

Good luck out there.

Laguna Freak

Well-Known Member
Jan 5, 2015
South Central Texas, just north of the Wall
I am using bergers ballistic program on their website, I shot at 300,600,1000 yards results were:
300 called for 3.93 moa. Actual 3.5
600 called for 12.46. Actual 12.0
1,000 called for 27.71. Actual 30.0

Specs: 33 nosler
M.V. 2,780 fps
263 grain hammer hunter
B.C. .325 G7 (from website)
Elevation 1,400 ft
Temp. 59*
No other factors added in.

What I'm looking to do is get chart to mirror real moa from drops @ 1,400 ft so I can adjust elevation to 9,500 ft for Colorado Hunting trip.

Do I just adjust the B.C value until it reads what I got from drops?

You can plug your data into the JBM Ballistics calculators for free to see if it yields a different / more accurate result. I know from experience there are substantive differences between Berger and JBM stability calculators.

Recent Posts