Savage 308 /175 SMK - Bullet Drop Question

Discussion in 'Long Range Hunting & Shooting' started by KPB71, Jan 1, 2011.

  1. KPB71

    KPB71 Well-Known Member

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    Question~

    This is kind of long (sorry), but I have included all the info I hope.

    I was out shooting today using a

    Savage 10 FCP HS precision
    1:10 twist and 24" barrel

    W/ Scope:
    Leupold Mark 4 LR/T M1
    Mildot 6.5-20x50

    Bullet:
    175 smk B.C. .496

    Lapua Brass

    CCI/BR2

    Powder:
    Varget 44.8 gr.

    I was shooting at 600 yards, temperature was about 5 degrees w/ no wind. The gun is zeroed at 200 yards. The scope was set at max power (20x).

    Noslers reloading guide drop table indicates that the drop for 600 yards at a velocity of 2700 fps should be -82.5.

    I set up a target marking the -82.5 drop, however, in order to hit the mark I had to use the 2nd mildot down in order to make the target instead of the 4th mildot.

    What should the bullet drop be at that distance based on the information above?
     
  2. SBruce

    SBruce Well-Known Member

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    Hold over should be anywhere from 3 1/4 to 4 mils, depending on your altitude............but you were making hits at 600 with only 2 mil holdover??

    Something is waaay off there. You would have to be shooting somewhere in the velocity range of 3500'/sec to use a 2 mil hold at 600 yds, according to the NF ballistic program.

    Other possibilities are scopes' zero shifted, scope moved in the rings, resting the barrel on something??

    Are you absolutely sure you were using 2 mils, and not 4??
     

  3. KPB71

    KPB71 Well-Known Member

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    Sbruce, The scope has four dots down and four across and i was on the 2nd one down what if i was zeroed at 300yards and not 200


    thanks Kenny
     
  4. SBruce

    SBruce Well-Known Member

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    Even zero'd at 300, drop would still be around 3 mils assuming 2700'/sec.

    Maybe look through the scope at a 100 yd target.......make sure there's 3.6" from the center of one dot to the center of the next dot. If there's alot more space then the scope isn't in mils. and needs to be sent back to leupold or you'll need to learn what it really is in.
     
  5. dodgefan

    dodgefan Active Member

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    If I'm correct you had an aiming point 82.5" above your expected impact point. Is this true? If you then had to hold an additional 2 Mils above the aiming point to hit the expected impact point. I would expect your velocity is not quite in line with the manual. The environmentals you fired in most likely don't match the manuals corrected environmentals either.
     
  6. Bravo 4

    Bravo 4 Well-Known Member

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    Sounds like your zero is more along the lines of 400!
     
  7. diriel

    diriel Well-Known Member

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    I do not think you were looking up the actual drop table for an Sierra Match King bullet. Pretty sure the drop tables in that manual are for nosler bullets, which can be a bit different.

    I would fire up JBM:
    JBM
    And see what it says. Also measure from center of scope body to center of bore line and see how far above center your scope is mounted. Input that measurement into JBM instead of the default 1.5". It makes a difference on drop tables, and it is a very common mistake people make.

    Good shooting,
    Gary
     
  8. Bravo 4

    Bravo 4 Well-Known Member

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    No, these numbers add up with the 175 SMK and his velocity (actual or estimated) of 2700fps. But with a zero of closer to 400 yards. We shoot the 175's almost exclusively out of our M24 and M110. To confirm my original post I just did a quick check with exbal and JBM. There is probably no way for him to get a 2 mil deviation at 600 yards by fidgeting with his scope height. There is something way off here, either his mil reading is off (and it doesn't seem to be) or his zero is. To get is drop with a 200 yard zero he would have to push that bullet around 3500fps at around 9,000 ft asl.
     
  9. KPB71

    KPB71 Well-Known Member

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    dodgefan: The answer to your question is Yes.

    direil:I checked and it looks like the center of scope to center of bore is 2".

    If it's a scope problem what do you think the problem is if it's not in mils?

    Thanks for all the suggestions and info all..

    Kenny
     
  10. liltank

    liltank Well-Known Member

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    My question is to what power is your scope to be set on for proper mil reading? Some scopes are specific to the power setting for the Mil-dots to read correctly unless you own a first focal plane scope which reads at any setting correctly.

    Tank
     
  11. KPB71

    KPB71 Well-Known Member

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    The distance between each mildot is 18" at 600 yds. From the center cross hair to the second mildot is 36". Would that be my drop?
     
  12. dodgefan

    dodgefan Active Member

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    OK we are part of the way to an answer. now a few more questions.

    1. Did you chronograph the load?

    2. If you did chronograph the load what temperature were you shooting in?

    3. did you verify the 200 yd zero before shooting the 600 yard target?

    4. What was the altitude/barometric pressure at the firing point?
     
    Last edited: Jan 2, 2011
  13. SBruce

    SBruce Well-Known Member

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    36 inches would be close to two mils at 600 yds. Actually should be 43". Bottom edge of one dot to top edge of next lower dot should be .8 mil (according to Leupold) which is 17" at 600 yds...........18" is pretty close.

    Actually sounds like you've got more along the lines of 3 IPHY dots......real close to 3 moa. A mil should be 3.6 IPHY.

    If your scope is 2nd FP, there is a certain power that it's supposed to be used at for the dots to exactly space 1 mil (as liltank said) so if you're on max power already, then turning the power down will space you out more.

    Sounds like the real problem is your zero distance. There is no way that you're zero'd at 200, more likely zero'd around 400 or further (give or take, depending on altitude)..........so yes, that being said........your drop at 600 is approx. 36" or 6 IPHY.

    Now go check at 200 or 300 yds, you'll be shooting pretty high at those distances something like 13-15 inches high at 200 and 300 yds.......worth checking IMO.
     
    Last edited: Jan 2, 2011
  14. KPB71

    KPB71 Well-Known Member

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    Dodgefan I dont have a chronograph, and i haven't verify that it is still on at 200yds,4300ft

    SBruce I was wondering about the scope set on 20x if that was the problem, this is my first time shooting at 600yds. trying to figure out how the scope works the Mil Dots.


    thanks for the info