.243win 75g vmax help

Discussion in 'Reloading' started by 1tonpower, Jul 7, 2013.

  1. 1tonpower

    1tonpower Well-Known Member

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    Im trying the 75vmax out. I have them loaded with 46.6g of h4350 @2.64"

    The 100 yard ground is inside a half inch. I moved back to 300yrds. Turned it up 3 moa and the fist shot hit 2" right and and 1" low of the center on my 10" plate. The 2nd shot was an inch right. The next two shots were at some rocks. Both of those shots connected..the 3 moa I got from my ballistic app with MV @3200. Scope hight is 2". I shot 400yards today and made contact with the same plate 4" hight 4" right. It was a little breezy. My app called for 5.45moa up.. I shoot and it hits center but way high. I dieled down 4 clicks and missed about 4" lower then the 1st shot... I made contact on the plate at 3.75moa u from my 100yd zero...the hit was about 4" high of center of the plate...


    Here's my question. I am getting a bass MV from the reload manual but so far it isn't adding up... I don't have a crono, I'm shooting a 26" 1:10. Can anyone give
    Me a better estimate on my MV. I know I need to shoot
    More then 3 rounds to validate this test. I'm going to check my 100yrd zero tomorrow to rule out that.
     
  2. c_bass16

    c_bass16 Well-Known Member

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    With a 26" barrel, I'm betting your shooting WAY faster than 3200.

    Get a bigger piece of paper. 24"x36" tag board works well.

    Take it out to about 7-800 yds and figure your drop. Dial, and see where you actually impact.
    Figure out what you would have to have for an ACTUAL velocity in order to be on target, move in closer to about 300 yds and check again with your new velocity as a standard.
    If it doesn't match up, then your BC data is slightly skewed.
     

  3. B23

    B23 Well-Known Member

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    FWIW, using your load info, QuickLoad says 3447fps and that you're on the high end of pressure.
     
  4. Sully2

    Sully2 Well-Known Member

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    Hodgen's chart says that with H4350 and 40.7 grains of it your at 4183 FPS and.....58,500 pressure....!!!!!

    AT 46 grains your REALLY pushing it
     
  5. 1tonpower

    1tonpower Well-Known Member

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    I got the load data from hornady's 8th edition. According to the book I'm a tenth under max. I did start low before I got this high. Bolt lift is easy and no primer cratering. Thanks for the responses. I will look over my spent cases from today to double check.
     
  6. Sully2

    Sully2 Well-Known Member

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    deleated
     
    Last edited: Jul 8, 2013
  7. 1tonpower

    1tonpower Well-Known Member

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    [​IMG]
     
  8. 1tonpower

    1tonpower Well-Known Member

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    [​IMG]

    This is from today. One hit at 510 yards with 7MOA up and one hit at 400 yards with 3.75MOA up.. There was a slight right to left wind.. I put 3500fps into my calculator and it gave me 6.96moa for 510... But called for 4.26moa @ 400.. I saw that impact high.. I can down to 3.75 and hit on the next shot. I'm using the listed 330BC for the 75vmax..

    Earlier today I set out 6 half gal juice jugs 2 each at 200,300 and 360.. 200 yards called for .75, 300 was 3.00moa and I dialed 3.5 for 360 yards. Once I made hits on them all I shot the remaining jugs in random order dialing for adjustments, hits were repeated.. How do I make the calculator more accurate.

    I'm using ballistic AE.
     
  9. c_bass16

    c_bass16 Well-Known Member

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    You're listed BC of .33 is either incorrect (It's an advertised number by Hornady) and is not working with your system. Or your optic is not tracking true.

    Bullet drop doesn't lie.

    3,4 and 500 yds is not far enough to "true" your velocity and bc.
    You're putting in bad info and you're getting out bad info.


    Edit...
    It would probably be easier if you list ALL of the data you're putting into your app so we can either try and duplicate, or correct the issue...because the drop chart you're getting doesn't jive.

    These are the numbers where you're making contact?
    200 - .75 MOA
    300 - 3 MOA
    360 - 3.5 MOA
    400 - 3.75 MOA
    500 - 7 MOA

    Just by looking at the numbers, something is WAY off.
    You need 1.25 MOA additional elevation to go from 200 to 300 (not impossible)....but then from 3-400, you only need an additional .75. This IS impossible.


    I'll give you the atmospheric data that I have here currently, with the published .33 BC and I'll show you what I'm talking about. This is not necessarily true for you, just an example.

    My station pressure is 28.45, temp is 80, powder temp is 80, humidity is 50%, velocity at 3500,
    Range card craps out numbers as follows.
    100 - 0 MOA
    200 - .5 MOA
    300 - 1.9 MOA
    400 - 3.8 MOA
    500 - 6.1 MOA
    600 - 8.8 MOA
    700 - 12 MOA
    800 - 15.7 MOA

    SO, if you take your rifle out and shoot at 800 yds, and you need 16 MOA to get on target...then one of two things is necessary. Either you're velocity is off or your BC is off. Take a shot at 400 and note where it impacts on the target.
    You'll have two TRUE numbers. 16 MOA at 800 and (for example) 4 MOA at 400.
    When you consult the range card, you see these don't match up, so either the velocity or BC is wrong.

    To check, you can adjust your velocity and bc until you get a combo that matches BOTH of your real world bullets.
     
    Last edited: Jul 8, 2013
  10. 1tonpower

    1tonpower Well-Known Member

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    Thanks.. I'll look for a spot to get 7-800 like you said
     
  11. Sully2

    Sully2 Well-Known Member

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    Yepper...I see it now and deleted my previous post
     
  12. 1tonpower

    1tonpower Well-Known Member

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    Brass 16: thanks for that. I understand temp and pressure are can affect the out put also. But it wouldn't account for the 3-400 yard confison I'm seeing.

    Next time I shoot I will see what it takes to get on target @800. Then shoot a group at 400 with with out changing the scope? Then messure the differance, Or should I adjust to 400yd zero
     
  13. c_bass16

    c_bass16 Well-Known Member

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    After you dial up to see what it takes to get to 800...you want to dial back down and see what it takes to be on point at 400.

    If you cant find a velocity that matches the trajectory at BOTH distances, then your BC is slightly off.

    Either way, the only explanation I can come up with for your 3-400 yd adjustment being so far out of wack, and still being on target at 500, is your turrets aren't tracking correctly.

    What atmospheric conditions are you using for your program?
    The only way I can figure it taking 7moa at 500 yds, is if your atmospheric pressure is way high, or if you're velocity isn't really as fast as your 400 yd dope says it is.
     
  14. 1tonpower

    1tonpower Well-Known Member

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    I had the atmosphere option turned off. Next time I shot I'll turn it on.