G7/Shooter/Exbal conflicts

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by D.Camilleri, Aug 3, 2014.

  1. D.Camilleri

    D.Camilleri Well-Known Member

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    I have been using exbal on my palm pilot for the last couple of years for my ballistic calculator for my 338 rum. I have used the program to verify my velocity and calculate my drops and it has worked pretty well. So, I moved up in technology and bought a smart phone and down loaded Shooter.

    Today I went to the range to get the cob webs off all of my rifles and thought I would refresh my memory with some fresh chronograph readings, so I dusted off my pro-chrono and shot most of my loads through to see if my memory was good. Last year I bought a beta chrono but it seemed to give me faster speeds than the pro chrono and neither seemed to be dead on. So I was using drop charts to verify my velocity. Today the pro chrono was showing 2730 for velocity.

    This brings me up to my shooting today. 338 rum ,300 grain berger otm, zeroed at 100 yards, 75 degrees, 20% humidity, 4270 elevation, I entered my go to velocity of 2830 and BC of .818 G1 into my exbal program for my 690 yard target and the solution was 15.25 moa, fired and it was on the money.

    Then I went to my phone and entered all the information into Shooter and it told me 13.2

    Then I entered the information into G7 ballistic calculator and it told me 13.7

    All of the ending velocities are different. What gives?
     
  2. Broz

    Broz Well-Known Member

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    They should not be anywhere close to that far apart at only 690 yards. My best guess is conflicting data entry. I would go over it all again and see what entry is misunderstood or wrong entry. Watch close on shooter for that powder temp / velocity area. I would zero it out for now.

    Also look close at zero entry data.

    Jeff
     

  3. D.Camilleri

    D.Camilleri Well-Known Member

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    Jeff,

    Thanks for replying. I went over all the data inputs very carefully and made sure the zero inputs are all the same. I turned off the powder temp on the shooter app also. When the shooter app wasn't jiving, I went to the G7 program and inputted the data again. None of them are matching. I have used my exbal out to 1250 yards with good hits, but I was thinking it might be nice to use the shooter app on my phone since it has a built in angle meter. What really doesn't make sense is that each of the three programs comes up with a different velocity when all the other inputs are the same. Almost like the BC is changed. Now I am really questioning what my actual velocity is.

    I just inputted the information for my 300 rum with the 215 berger that I tested today at 690 yards. 3100 velocity, exbal gives 11.75 moa with a 100 yard zero, G7 gives 11.8, all of the other information is the same as the 338rum. ?????? 11.75 was right on the money on paper.
     
  4. bigngreen

    bigngreen Well-Known Member

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    What was your Baro pressure?
     
  5. lamiglas

    lamiglas Well-Known Member

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    Exbal used to be our primary program, and then when we starting using shooter we input all of our data for several rifles and checked the two programs against each other. With no incline or decline they were always nearly identical. Never off by even 1/4 moa. I can't give you an idea of what is off by I am fairly confident that something in your input data has to be off. I know that can be frustrating and I wish you good luck in Figuring it out.
     
  6. Broz

    Broz Well-Known Member

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    Yes Sir. I would keep looking. They should be real close just like they are for your 300 with 215's.

    Jeff
     
  7. D.Camilleri

    D.Camilleri Well-Known Member

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    It is acting like the different programs are calculating the bc differently, because both shooter and G7 are giving higher end velocity by about 100+ fps. These are just mathematical equations, but even shooter isn't matching G7 and neither are close to the exbal. I even tried adjusting the velocity down to 2730 and entered it into the G7 and the drop still isn't close.

    With the exact same inputs including 29.8 baro, ending velocity with G7 is 2112 and 2075 with exbal and 2207 with shooter all starting with 2830 as starting velocity, .818 bc g1, 4270 elevation, 75 degrees ambient temp, 20% humidity, 100 yard zero, 0 at zero, 0 incline, exbal shows up 15.25 moa, G7 shows up 13.9, shooter shows up 13.2
     
  8. D.Camilleri

    D.Camilleri Well-Known Member

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    I just input my data into applied ballistics calculator and in order to match my drop of 15 moa at 690 yards, I had to use 2730 as my mv. I then input 2730 mv into exbal and matched all the other data. Exbal gave me 17 moa of drop. ??????????
    2730 was the velocity my pro chrono was showing today. It was also showing 3100 with my 215's out of my 300 rum and those matched both shooter and exbal.
     
  9. bigngreen

    bigngreen Well-Known Member

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    I ran your info in Applied Ballistics which matched Shooter, ran a trajectory validation to match your Exbal and it came up with a velocity of 2672 fps to match. Something seems really out of whack, sorry not any help!
     
  10. D.Camilleri

    D.Camilleri Well-Known Member

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    The longest shot that I have made with exbal on this gun was 1242 yards. I put the info into exbal, with 2830 mv and it shows Up 39 moa, then I put in Mv 2672 into shooter and it shows up 36 moa. Something is whacked. I wonder if the exbal program has a glitch. Funny thing is when I dialed what exbal told me to, I hit!
     
  11. D.Camilleri

    D.Camilleri Well-Known Member

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    I just compared my friends data for his 338 rum and in order for the drops at 690 to be close, the velocity input to shooter had to be 70 fps less than the velocity entered into exbal. These numbers were using sierra match king with the litz bc of .745. I had to drop the velocity we had used shooting out to 1242 of 2690 down to 2620. So which calculator is right, shooter or exbal?
     
  12. BEEMAN

    BEEMAN Well-Known Member

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    My friend had a similar problem last year. It ended up being the LOOK ANGLE on shooter. He didn't realize that it was not set to 0 degrees. It really threw us off.
     
  13. lamiglas

    lamiglas Well-Known Member

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    I gave away my exbal programs/pda's as we have been using bullet flight for awhile now. Last year I was helping a friend validate his rifle. On the exbal I gave him let's say it was callng for 23 moa at 1000 yards.. Well, he hit 10" low. We went to trajectory validation and put in the distance. When you do this it propagates the come up in the field next to distance. On his it wasn't propogating the number it gave us for the sollution, so when we put in 10" low it calculated to the wrong velocity. We went back into the solution page using the new velocity and put in 1000 yards and the come up was not right. We knew we needed a solution that gave us 1 moa more, (24 moa) so we just played with velocity until we got it to give us 24. I gave him two PDAs with exbal. The other he hadn't used. We got it out and plugged everything in using his initial velocity. It called for 23, moa. Went to validate, put in 1000 yards and the field next to it propagated a come up of 23 moa like it should. We put in hit 10" low and it validated correctly. Once we hqd the right velocity his glitched out exbal worked and gave the right come ups. But the trjectory validation part was very messed up. I forgot all about this until you mentioned that your exBal may have a glitch. Try plugging in 1000 yards and looking at the come up it gives you. Go to validation screen and put in the distance. Click on the come up field and see if the come up that propagates is the same number it gave for a solution. It should be.
     
  14. D.Camilleri

    D.Camilleri Well-Known Member

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    I just ran a hypothetical test: 338 rum 225 accubond, bc g1 .550, mv 3300, alt. 4242, baro 29.88, temp 82.0 incline 0, distance 1000 yards. Exbal shows ending velocity 1779, time of flight 1.2426, energy 1580, elevation, -210, moa 20.0

    With the same inputs, shooter gives me velocity, 1948 time of flight, 1.186, path -195.1, path moa U 18.6

    If I do the tradgectory validation to match the shooter drop, exbal raises the calculated mv to 3452

    Is it time to dump Exbal?