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I've been using JBM for years and always recommend it when people are looking for a ballistic program. Good program and pretty accurate too if you put in the right numbers. I used JBM dope when i won Tac Pro's sniper match this year. It's what you have to do when you live in the land of the 200 yard ranges.

JBM also has a program that makes cards. Here it is
http://www.eskimo.com/~jbm/ballistics/t ... _card.html
 

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Rob01 said:
I've been using JBM for years and always recommend it when people are looking for a ballistic program. Good program and pretty accurate too if you put in the right numbers. I used JBM dope when i won Tac Pro's sniper match this year. It's what you have to do when you live in the land of the 200 yard ranges.

JBM also has a program that makes cards. Here it is
http://www.eskimo.com/~jbm/ballistics/t ... _card.html
Thank you for posting the trajectory card one, i'm going to make quite a few of those up and laminate them!

Branden
 

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i just compared the JBM program with the Milldot Master i just received and its close but not perfect
 

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smsnyder said:
i just compared the JBM program with the Milldot Master i just received and its close but not perfect
How close? Within 1%? 5%? 10%? Can you elaborate a little?
 

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I would say 5%. the mildot master scale is hard for us old people to read with failing eyes
 

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HORNADY'S WEBPAGE HAS THE SAME THING! GO TO THERE PAGE AND GO TO BALLISTIC RESOURCES. THEY HAVE SEVERAL DIFFERENT OPTIONS TO CHOOSE FROM. I USE IT PRETTY REGULARELY!!
 

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I dont hear anyone comparing them to real life...I use JBM, dont want to pay for a program yet, and Im not quite sure why I bother. Its decent enough to get you out to 500yds but not perfect. After that its anywhere from 2-6moa off, even with just the right conditions plugged in etc.

Its possible that the BC of the bullet is slightly different than advertised, Im about 3-4moa lower than JBM calls for at 1000.

Other than it not being right, JBM is a great calculator, its easy to use and gives good data.
 

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Calculating BC

Ok, this is a little off the topic but along the same lines and I didn't want to start a new topic just for this question.

I am new to long range and re-loading. I've got a great ballistics application on my iPhone called bulletFlight that seams very capable of anything I need for long range calculations.

The problem I am having is that I don't know how to get the BC of my bullets and my gun and I don't understand what drag model (G1, G2, G3 etc...) is or how to know what my bullets classify as.

Can anyone help me get the most out my program? I am using Sierra Match King bullets in 168, 175 and 180 with a muzzle velocity of 2730 fps or so at about 800 feet above sea level.

Do I need two Chrono's to find my BC? Is that pretty standard for my lead or is it very specific to custom loads? Any help (think "BC for stupid people") would be greatly appreciated.

Thanks,

Jarem
 

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BC is ballistic coefficient and really describes how well your bullet flies through the air- the closer to 1 the more cleanly the bullet cuts the air.

If you look in your reloading manual the particular bullet BC's should be listed. If you don't have a reloading manual to reference you can check out the sierra website:
http://www.sierrabullets.com/index.cfm? ... efficients
Look up your bullet diameter and weight and SHAZAAM! there it is.

The wonder of the internets.
 

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On-line ballistic calculators

Can anyone tell me why I get 10 feet difference on the JBM calculator as compared to Mel's drop charts on the ammo reviews. I am getting
-384.6 drop at 1000 yrds on JBM with all the right numbers punched in-is this right?
 

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Probably need to de-sticky this, both URL's (calculator and card generator) are dead links.
 

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wind drift for 308

I am new to this long range shooting with a scope i have used iron sights out to 500 yards in the past and done really well but am now shooting a Rem 700 ADL in 308 and am trying to find some way to estimate wind drift on a number of diff rounds does anyone know where i can find it.
 
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