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Thread: Ballistic Calculator Problems

  1. #1

    Ballistic Calculator Problems

    Help!

    I am using the Ballistic FTE app on my Iphone but I am having a few problems. I know the muzzle velocity etc, but using the 1/4 click values at 300 yds it states 17 clicks when I need 22 to get on target, and 29 clicks at 400 when I need 35 clicks, the only way that I can get the calculator to represent my own data is to lower the BC value from .43 to .28, but is this right, and will the windage adjustments still be accurate on the calculator?
    Last edited by Cumbrian 1; 13-02-2012 at 09:30.

  2. #2
    I've got the same program on my iPhone. I just use it as a guide. So maybe just add 5 clicks onto what ever it says and it should get you on the board. Then the rest is down to experience with your rifle and ammo.

    Other option is to Down load the free swaroski app and check the FTE data against it.

    Jase.

  3. #3
    That seems to be along way out to me Cumbrian. I use Ballistic FTE and have always found it very accurate.
    Have you double checked that the info you put in is correct?

  4. #4
    I shall start from scratch again, and double check the muzzle velocity and 100 yd zero, and reshoot some targets, the groups were okay but low, I had a lot of faith in the calculator but had only shot reactive targets and never checked on paper except for zeroing the exact POI.

  5. #5
    Quote Originally Posted by Cumbrian 1 View Post
    Help!

    I am using the Ballistic FTE app on my Iphone but I am having a few problems. I know the muzzle velocity etc, but using the 1/4 click values at 300 yds it states 17 clicks when I need 22 to get on target, and 29 clicks at 400 when I need 35 clicks, the only way that I can get the calculator to represent my own data is to lower the BC value from .43 to .28, but is this right, and will the windage adjustments still be accurate on the calculator?
    The old addage of "garbage in, garbage out" applies. The published BC is only relevant to the circumstances under which it was calculated. Velocity, barometric pressure, temperature, humidity... all effect the real BC of a bullet. Many BC's are determined by computer, not actual firing. This is why when I test a new bullet and want to generate data on it, I use two to three chronographs in a line, measuring the velocity at 50 and 100 yards as well as at the muzzle. Then I do the math. It's the only way to get accurate data. Chances are, the app extrapolates your data to come up with a realistic ballistic picture. Plug it in and verify the results.~Muir

  6. #6
    I use the data from the ballistic app as a start point then I shoot groups on targets to 100, 200 and 300yds (and further if possible,) then adjust the fps and other data until it gives me back the correct drop.
    I know it can expensive this way but I enjoy shooting so I don't think about the cost.

  7. #7
    The old addage of "garbage in, garbage out" applies. +1
    ensure you are putting station preasure in not barometeric preasure this dose matter http://www.arcanamavens.com/LBSFiles...ownloads/Baro/

  8. #8
    Just a quick update for people who may have been interested, the problem was user/shooter error. My range is indoors I lye down on a concrete floor and shoot out to 500yds, I was shooting of a bipod, this was causing the rifle to shoot erratically. This problem does not happen when I use the bipod on grass, I used a front and rear bag and the difference was noticeable. I shot on a sunny still day and at 300yds the bullets were in or cutting the edge of a 3/4" bull, at 350 yds the holes were just to one side of the bull (there was a breeze) but the elevation was perfect in fact both holes were touching! At 400 yds I was getting a 4" group but I think the difference in the spread was down to me.

    Did I say that the Ballistic FTE app is the best ever.
    Last edited by Cumbrian 1; 27-03-2012 at 11:59.

  9. #9
    500 yard indoor range Is this accessible to all ???

    Looks like you have sorted your issues but I was going to say, where possible, use a G7 BC (most software defaults to G1 which is not relevant to modern projectiles) Also... Don't trust your chrono.. use the speeds you have gained as a guide only.. when you have found out the actual clicks needed at various ranges, work it backwards in Ballistic FTE and adjust the MV until BFTE gives the correct number of clicks.. you should find (as I did) that everything works in the real world after doing that.. AND... as Muir has sid... make sure you use accurate atmospheric data within BFTE.

    Don't start adjusting BCs in the software, that will more often than not produce undesired results and give differing levels of accuracy (BFTE vs reality) at different ranges.
    Last edited by Vipa; 27-03-2012 at 13:01.

  10. #10
    [QUOTE=Vipa;350229]500 yard indoor range Is this accessible to all ???

    My mistake only the firing position is inside, sadly it is on my brothers property and his wife can get the serious arse if we sit around all day shooting so I try to do it every 2/3 weeks, I did advise my brother that he should seriously consider getting a new wife.

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