Range Report Ballistic Card with Density Altitude

[Slope]

New to the forum, glad to have found it and hope to learn a few things to improve my long range shooting.

I will start with the question concerning using DA with ballistic cards.

Most of my shooting has been just out to 600 yards, and I am wanting to start getting out to 1000. Since my range has been limited to 600 I have just made up my own ballistics cards using my location and never really worried too much about taking into account humidity, pressure, and temp. I have recorded my zero summaries for temp change but that is about it.

My question is:How do I used a simple density altitude chart with my current ballistic cards. Do I need to make a new cards at say 500 ft elevations and then use the DA to adjust for my altitude and temp?

For instance, if I use a chart like what the FDAC has on it and determine that at 2000ft with a temp of 80 deg F that my DA is really 3500 ft. Now would I just turn to the card that I made at 3500ft and use it for my adjustment?

Could I also use the tables from Manual Calculation of Density Altitude to essentially get a slightly more accurate DA and again use it with a range card for the corrected DA? 29.92-(2000/1000) = 27.92 or a pressure altitude of 1824 which used on the DA chart at 80 deg F gives around 3750ft

Or does the ballistic card need to have the DA factored into it to work?

Basically I am trying to get away without having to use electronic software at the range. I could use one of the programs on my tablet, but I would rather use cards and charts that do not need batteries.

I really appreciate you help.

Thanks,
Slope

 

[Slope]

Anyone have any knowledge about this?

 

[WRM]

Or does the ballistic card need to have the DA factored into it to work?

This is the key. The trajectory varies due to DA - higher the DA, the "flatter" the trajectory is, because the atmosphere exerts less drag on the projectile (the air is less dense). That FDAC that you mention is a chart with multiple trajectories, so that when you set it for your DA, it gives you the solutions for that specific DA for that load.

I'm a "slide rule" fan, so I like Accuracy 1st's "Whiz Wheel". You can have custom wheels made to tailor for your load, so you're not stuck with the "off the shelf" loads for 308 Win, 300WM and 338LM.

 

[Rthur]

For the price of a Ballistic App, get one. I have used Bullet Flight and Ballistic AE. With a little fine tuning they will get the job done fine.

Had a dope developed at 1-1500 da shot at 8500+da and it was as close as I could shoot.


R

 

[SRSDriver]

I use JBM ballistics and then verify the data, but use it to generate cards for a range of DA. When I get where I'm shooting, I measure the DA and pick the card that makes sense.

 

[Grizzdude]

What I use for no electronic situation is the Whiz Wheel. It has the density altitude incorporated into the ballistic solution, as long as you know your temp and altitude your good to go. I have them for my .338 lapua and .308 loads. They are spot on when compared to AB ballistic software. Here is a link so you can get a better understanding https://www.accuracy1stdg.com/store/itemDetail.cfm?prodID=504 They might seem confusing at first but it only takes a few minutes to learn how to use properly.

 

[LastShot300]

For creating DA cards I rely on Patagonias's ColdBore. That way I know my cards are not based off approximate values like the FDAC, since they are created upon my exact inputs. On the other hand, creating them with CB1 is a no brainer, just takes a single click, and ready to export to PDF, WPS or Excel. Again, just a click and zero compromises.