Exbal question

Discussion in 'Equipment Discussions' started by royinidaho, Sep 8, 2009.

  1. royinidaho

    royinidaho Writers Guild

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    Does Exbal have an entry for chrono reading and determine MV when chrono is 10' away from the muzzle?

    If so I can't seem to find it.:rolleyes:
     
  2. Eaglet

    Eaglet Well-Known Member

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    No it does not!

    This is a copy of the e-mail that I sent to G Perry and he did never answer it:


    ----- Forwarded Message ----
    From: Javier O Moncada <xxxxxxxxxx.com>
    To: gperry@perry-systems.com
    Cc: yyyyyyyyyyyy.com
    Sent: Tuesday, January 23, 2007 2:15:37 AM
    Subject:

    Dear Sr.,
    From time to time I check for upgrades for the pocket pc.
    One nice addition for the Exbal program would be the ability
    to calculate muzzle velocities in the field by providing distance
    to chronograph and the reading. Do you have any plans for that
    in the near future?

    Sincerely,

    Javier O Moncada
    Carson City, Nevada.
    -----------------------------------------------------------
    LB3.0 on the other hand will do that and more!


     
  3. trueblue

    trueblue Well-Known Member

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    Roy,
    I can't imagine that 10 feet is going to make much difference in your velocity reading. I wouldn't worry about it. I'm sure you validate your drops.
     
  4. AF Shooter

    AF Shooter Well-Known Member

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    some where on here a person posted that per a conversation with Sierra (not sure) to add 2.1 fps per foot to chrono. Seems like it was fairly recent.
     
  5. royinidaho

    royinidaho Writers Guild

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    Well..... That's about a 10 point penalty for Exbal.

    I'm one of those fellas that doesn't get along well with Windows designed (read too many clicks and screens) User Interfaces. This mainly due to being a little intolerant in some things, this being one.

    The computer code should bring it all together in a single user interface and spit out the various reports per selection.

    Note the recent thread regarding Gus @ Patagonia.

    Also this is why I'm a Mac user except for the few special business programs that require MS programs that are not Mac friendly. I also use Parallels to run the MS stuff on the Mac. It does a fine job.
     
  6. jmason

    jmason Well-Known Member

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    Roy, if you have an Avg MV go to JBM ballistics. you can use it to figure out your true MV. You can also email it to me and I'll plug it in for you.
     
  7. topwater225

    topwater225 Well-Known Member

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    I'm with TrueBlue on this one....I may be missing something, but I don't see a benefit worth the time to code in the enhancement.

    The Trajectory Validation feature will calculate what your true velocity is if you are checking your drops for different distances.

    I think a more beneficial enhancement would be for Exbal to calculate a true BC when using the Trajectory Validation, as it only calculates velocity.
     
  8. jmason

    jmason Well-Known Member

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    I've found the velocity difference to be 10-20 PFS based on where you set up your chrony. Exbal doesn't correct your MV it changes it to what it needs to be to make future calculations. It "fudges". The further away you get the worst it can be. With exbal you probably won't ever be using the correct MV or BC. You'll be using #'s pulled out of the sky that seem to work up to a certain distance then Drag model is the next hurtle. You won't get over that one with exbal.

    I agree that for many there may be no benefit as far as hunting goes. hunting targets have big kill zones(large game). If your like me, Roy, and some others here, you'll get frustrated with "close enough". You'll want your impacts on target to only vary in their elevation because of your (my) less than perfect skills not because of less the perfect software predictions.

    Please don't be offended by my response as It wasn't meant to offend. Just wanting to point out that some people prefer a little more precision than others.

    As an example, If I go to the range and shoot paper at 500 yards using my software for predicted drops and I print a group that is .5 MOA low or high it really irritates me. My group could be two MOA in circumference but I want the center to be split by the horizontal line on the target. Any one of the shots would have harvested the intended game at that distance but the prediction isn't precise.
     
    Last edited: Sep 9, 2009
  9. topwater225

    topwater225 Well-Known Member

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    No offense taken what so ever. Thanks for explaining that part. I can totally understand where you are coming from now. I didn't think of exbal coming up with velocity numbers like you explained. I went out just this morning and my drop chart is VERY GOOD to 1000 yards (on steel). But I know what you mean when you say on paper...For instance, this irritates me: I started at 500 and was dead on. So, I went to 1000 and I was dead on (as far a drops go). So I move to 900 and now I am hitting the top of the plate. I was still hitting the 12" steel plate, but instead of dead on like 500 and 1000, now I'm at the top. I was somewhat pleased because I was hitting the plate, but if I were shooting paper for score, that might really suck. After that I went to 825 and sure enough I was dead center.....same for 650. I may be referring to a different problem, but there is definitely room for improvement.
     
  10. Eaglet

    Eaglet Well-Known Member

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    +1 I love knowing exactly what my correction should be. Many times because of the muzzle brake blast I have to put my chronograph farther than 12' and on top of that I already have the ES in my load to deal with... If my attitude is close enough, what use is there to use spin drift correction, Coriolis Effect correction at long ranges? That would be like start out as a long range blaster and want to end as a precision long range shooter. The more precise the data I collect, the better chances I have at long range to hit the target.

    If you're going to be shooting to 300, 400 yards then by all means you can get away with the drop chart that comes in some ammo boxes. :D
     
  11. jmden

    jmden Well-Known Member

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    Roy,

    Use JBM's online ballistics program for that. It adjusts based on your chrono reading and you tell it how far away from the chrono you are in whatever units you measure with. It'll spit out your MV on the '0' line on your drop chart down below.

    JBM - Calculations - Trajectory (Drift)

    This page now calculates (and can be included in the firing solution) your gyroscopic drift as well based on Litz's calculations.

    Hope this helps,

    Jon
     
    Last edited: Sep 9, 2009
  12. topwater225

    topwater225 Well-Known Member

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    Good information, guys. I like perfection as the next guy :D

    However, after messing around with the chrony distance with JBM, I didn't see a difference from 6 feet to 13 feet. It finally changed from 22.2 moa to 22.1 moa after using 14 feet for the chrony distance. If you could input .1 moa in your turret, I'll bet you wouldn't see hardly any difference.....and that's at 1000 yards.....AND just because I shoot mostly steel at 1000 yards doesn't mean "close enough" is good enough AND I do not even reference 300 - 400 yard stuff. If a guy invests in Exbal and uses it a lot, I doubt he even has 300 - 400 yard distances on his mind.

    Just playing devils advocate here..... :D:D
     
    Last edited: Sep 9, 2009
  13. trueblue

    trueblue Well-Known Member

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    My post did not mean that I go with " close enough". I just don't see the difference from validating your trajectory with the MV from 15 feet from the muzzle with a chrono reading or validating your trajectory with the known velocity at the muzzle. In both instances it still needs to be done.
     
  14. royinidaho

    royinidaho Writers Guild

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    Thanks guys.....

    I use JBM and anything else that is available to me.

    I do my shooting at paper. I have the wall thick with shot targets.

    It would be nifty if JBM could be made mobile......gun)