New JBM range card

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by AJ Peacock, Aug 7, 2009.

  1. AJ Peacock

    AJ Peacock Well-Known Member

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    A couple weeks ago, I sent in a request to JBM for an enhancement to their range cards. I use the Nightforce NP-R1 Reticle, shown below. It has 40 moa graduations (10 above the crosshair and 30 below the crosshair). I normally build my range card by repeatedly running the ballistics programs until I figure out the exact yardage that each of the graduations represent. I set my zero so the top graduation (10moa above the crosshair) is set for 100yds.

    Well, JBM made it easy with their new range card. They call it a 'constant drop' range card, as it will give it's output for a specified constant drop (every 1/4moa for example). I ran it for my 338Allen mag, 7480ft elevation, 3270fps,10mph wind and a constant drop of 1 moa to match my reticle. My zero is 731yds and viola! the following range card magically appears. The little note at the top of the rangecard is from the notes field at the top of the input screen. With this range card, I can shoot out to a mile without touching the elevation knob.


    [​IMG]

    Enjoy,
    AJ
     
  2. LouBoyd

    LouBoyd Well-Known Member

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    Looks like JBM's new card will work for mil-dot scopes too, at least for shots of up to 34 moa (10 mils ) of drop from the zero.

    Thank you JBM for the card generator and AJ for stimulating it's existance.
     
    Last edited: Aug 7, 2009

  3. AJ Peacock

    AJ Peacock Well-Known Member

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    It will output for Mil and will go further than 10mils, it is designed to go to 120 graduations.

    AJ
     
  4. LouBoyd

    LouBoyd Well-Known Member

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    The program and the table it genrates aren't the problem, The vast majority of mil-dot scopes only have ten mils of calibration on their reticles.
     
  5. AJ Peacock

    AJ Peacock Well-Known Member

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    Oh, that makes more sense. I've looked thru mildot scopes, but never really used them.

    AJ
     
  6. royinidaho

    royinidaho Writers Guild

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    AJ,

    Well by durn, I just knew you were good for somethin':)

    It's not often you can get what you desire implemented! Good goin'

    PM your addy and I'll send, if you wish, some paper to print it on that will not run in the rain.

    All ya do is print using a ink jet printer then wipe with damp cloth which fades it a bit but fading stops there.

    My understanding is that if a laser printer is use with this paper that there is no fade what so ever.......

    Just a tho't.
     
    Last edited: Aug 7, 2009
  7. AJ Peacock

    AJ Peacock Well-Known Member

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    20 years as an IT manager and managing development teams must have taught me something about how to ask for software changes :D

    AJ
     
  8. LouBoyd

    LouBoyd Well-Known Member

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    AJ, you must be good. I cant' even get people I PAY to wite sofware to make it do what I want ;-)
     
    Last edited: Aug 7, 2009
  9. royinidaho

    royinidaho Writers Guild

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    AJ,

    Yup, you're a smooth talker.

    I just bought an NXS with the NP-R! reticle.

    I know nothing about them. I didn't even know they had a knob for illuminating the reticle.:rolleyes:

    Are you saying that the NP-R1 has 30 MOA on the vertical with each large hash mark being 2 MOA and the smaller being 1/2 that?

    With out study, I just figured it was 15 MOA vertical.:rolleyes::rolleyes:
     
  10. AJ Peacock

    AJ Peacock Well-Known Member

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    It depends on what the magnification is on your scope. If it is the 22x, then you have 10moa on top and 20moa underneath (total 30moa). If it is a 15x like mine are, you have 10moa above and 30moa below.

    Yes, 1moa and 2moa length on hashmarks. There is a pdf file you can find here that goes into detail for their reticles.

    http://www.nightforceoptics.com/Reticle_booklet_final.pdf

    You will absolutely love the reticle. I practice using the reticle with the picture I posted earlier, I'll pick a range, look at my drop chart and then put my mouse on the correct spot of the reticle. As long as you remember what your zero range is, it's easy to remember whether to count above or below the crosshair.

    AJ
     
  11. RockZ

    RockZ Well-Known Member

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    AJ,
    Nice work! I love that site but haven't been to that page.Thanks buddy
     
  12. Ratwhiskers

    Ratwhiskers Member

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    l've used JBM to good effect for my shooting, just to give me the drops l need to "wind up" for a given/laser'd range.
    l'm planing to be in Africa next year and this new card will greatly help me to zero at a longer range and "hold under" when l need to for the odd quick shot at a closer range.
    My thanks and compliments to the programer.....
     
  13. fr3db3ar

    fr3db3ar Well-Known Member

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    Can you show your input setup to get those results? I'm obviously doing something wrong as I keep getting an error.

    pm_tj_derivs(): Y(d->v) < DBL_MIN.

    I'll call myself new to long range...and a newb to what that refers to.


    I got it to work....and still don't know what I had wrong lol

    Well, it seems I can get it to work for my .223 but can't get it to work for my 22 WMR. hmmm
     
    Last edited: Aug 9, 2009
  14. LouBoyd

    LouBoyd Well-Known Member

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    Some computer programs require input data to either be floatiing point numbers or integers explicitly. If the examples have decimal points, use decimal points in your input . 5.0 vs 5 for example.