My first Ballistics Card - Tips, Critiques and recommendations

[loudandproud]

Hello,

So, I am trying to expand my horizons to some longer distance precision shooting. Im moderately experienced out to 500 yards, but have had very little opportunity until now to shoot farther. I figured the first place to start is to upgrade my equipment and build a good ballistic card. I have recently ditched my Millett LRS-1 and have stepped up to a Bushnell XRS (love it).

I did some OCW development and found a nice load for my .308. 3/8th -5/8th MOA consistantly. Extreme Spread of 15 FPS over 20 shots. 2643 FPS mean velocity.

I used JDM ballistics to build this little table. Cut it down to size and it fits well in my pocket with my book and calculator. The gray adjustments are based off of powder and atmospheric temps @ 29.92 inHg. The tan data is my "barometric modifier" which was configured at 60* F. The percentages listed under the pressures (in tan) are percentage modifiers that are meant to applied to the wind data.

So... check my logic. Lets say I was calculating a firing solution at 1000 yards for a 30*F day, at 28inHg, 10*downhill, 7mph Crosswind at 60* left.

Elevation Logic:
(1000 x .984(cosine of angle))= 984 yards.
984>> U10.9 MILS -.5MILS (baro value) = U10.4 MIL

Windage Logic:

-.3 (spin) + (2.9 x .7(speed) x .91 (baro) x .9(angle)) = ~1.4 RIGHT

Anyone finding anything suspect with this method? It checks out pretty close to the JDM ballistics. I just want to make sure im not making any theory errors.
Any idea, suggestions or critiques for my card?







Thanks fellas,

Bryson

 

[NOMAD]

Looks like a lot of hard work and effort went into them Good work.

We offer these and they are dead on
Adaptive Quick Card (AQC)

 

[Ultraman550]

NOMAD,

how do these compare to the phone apps like Shooter, Istrelok etc.. Are they more accurate?

 

[NOMAD]

They are ran using virtually the same formulas. The formulas used on these are the same as the FDAC units. Only difference is its a page, its cheaper to produce and sell to the shooters that's why you wont ever see any new FDAC units.

The AQC is a way to get DA data effectively into shooters hands.

 

[djarecke]

So the first step would be to chrono our loads and then provide you with that information (along with bullet info) and you would print up a set of custom cards?

 

[jdknotts1]

I'm in the midst of making my ballistic charts myself. As a test run when I was using a friend's rifle, I watched Tibo-rex's videos and used his method. As I found out, they are all very close, and close will get you hits at short-medium ranges. I'm finding out as I move along, I'm plugging actual data into the charts and manipulating the rest as I go.
I used JBM and followed Tibo's method to get started. I'm still kind of torn between using density altitude method over baro/temp calcs. And I don't have enough experience yet to make a educated decision on which to go with.
Thoughts NOMAD? Baro over DA or vice-versa?

 

[J-Ham]

Yeah, the Adaptive's are the cat's meow!

Personally I like DA because it is just one simple number that factors in the major things that your bullet cares about as it's flying through the air... Then all you (the shooter) have to do is get your hold for wind right, apply all your fundamentals of shooting & get your hit... Easy enough right? Haha