BC always better on lead core bullets vs. copper. Why?

Discussion in 'Long Range Hunting & Shooting' started by Jed Eckert, Sep 22, 2019.


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  1. Jed Eckert

    Jed Eckert New Member

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    Howdy,
    I live where you must shoot lead free while hunting 100% of the time.
    Barnes/Nosler lead free bullets may perform well on game, but by the numbers, have lower ballistic coefficients than similar weight lead counterparts.
    I know lead is more dense than almost every material we can use for bullets.
    Why are the lead bullets more efficient?
    Ie Barnes LRX, vs Nosler ABLR.
    To make it expand must the bullet be less efficiently constructed? Wider meplat?
    Manufacturing process?
    .338 wm vs .300 wm. .338 wm seems to win in lead free department.
    Any ideas? Thanks
     
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  2. yorke-1

    yorke-1 Well-Known Member

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    The easy answer is that bullet weight is a factor in BC.

    I don't get terribly hung up on BC for a hunting bullet; I'll take consistent and predictable terminal performance over BC any day. What are you hunting and how far are you expecting your shots to be?
     
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  3. bearcat2

    bearcat2 Well-Known Member

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    You answered your own question. Lead is denser. For the same weight and diameter you will get less drag on a smaller mass. Unless you are going too small to make them aerodynamically efficient (ie round balls). As long as you are using enough mass to make a bullet aerodynamic less mass=less drag=higher bc.
     
  4. Jed Eckert

    Jed Eckert New Member

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    Thanks for your time.
    Currently I'm using barnes 150 ttsx out of a .30-06 for blacktail deer and pigs to 500 max. Plan on going to barnes 175 lrx and adding elk in the coming year. For whatever its worth on wikipedia, It looks like Mass is an integral part of the equation, I should have looked it up before I asked.
    Projectile diameter and the shape of the projectile and are also very important.

    "The formula for calculating the ballistic coefficient for small and large arms projectiles only is as follows:

    [​IMG] [2]
    Where:

    • BCProjectile = ballistic coefficient as used in point mass trajectory from the Siacci method (less than 20 degrees).[3]
    • m = mass of bullet
    • d = measured cross section (diameter) of projectile
    • i = Coefficient of form
    The Coefficient of form (i) can be derived by 6 methods and applied differently depending on the trajectory models used: G Model, Beugless/Coxe; 3 Sky Screen; 4 Sky Screen; Target Zeroing; Doppler radar.[4][5]

    Here are several methods to compute i or Cd:

    [​IMG] [6][5][7]
    Where:

    • i = Coefficient of form.
    • n = number of calibers of the projectile's ogive.
    Where n is unknown:
    [​IMG] [6]
    Where:
    • n = number of calibers of the projectile's ogive.
    • = length of the head (ogive) in number of calibers.
    or

    A drag coefficient can also be calculated mathematically:

    [​IMG] [8]
    Where:

    • Cd = drag coefficient.
    • [​IMG] = density of the projectile.
    • v = projectile velocity at range.
    • π (pi) ≈ 3.14159
    • d = measured cross section (diameter) of projectile
    or

    From standard physics as applied to “G” models:

    [​IMG] [9]
    Where:

    • i = Coefficient of form.
    • CG = drag coefficient of 1.00 from any “G” model, reference drawing, projectile.[10]
    • Cp = drag coefficient of the actual test projectile at range."
     
  5. codyadams

    codyadams Well-Known Member

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    Yup. Lead core bullets are denser, if you use shotguns much, think of lead shot vs steel, lead shot carries energy better and hits harder than the same size steel, and even if you get pellets with similar weight, such as lead bb's vs steel T's, the smaller diameter heavier lead shot will still hit harder and penetrate better than steel.

    If your shooting inside 500 yards, the bullets bc isn't a huge deal, though still worth considering if there are multiple bullets that will work. At 500, comparing a high bc Berger 180 going the same velocity as the 175 lrx, the 180 berger has about .5 MOA less drift in a 10mph wind, so about 2.5-3"....very little at that close range. On a different note, I personally would look at the hammer bullets vs Barnes, they are overall fantastic mono bullets.
     
  6. LVJ76

    LVJ76 Well-Known Member

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    Second that for Hammer bullets
     
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  7. tooth doc

    tooth doc Well-Known Member

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    Try
    165 or 168 ttsx in your 06. Have used for many years in my 300wsm. Have killed everthing i've used it on, up to huge eland bulls, 3. Many kudu, blue wildebeast, waterbuck, zebra, deer, elk and about 20 black bears. Never failed to perform.
     
  8. ajkellerusmc

    ajkellerusmc Well-Known Member

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    I have years of experience with barnes and some have been hard to get to shoot accurately. The best accuracy I achieved is with the TSX which looks like an OTM bullet. Had bad results with both the TTSX and the LRX which both have the blue aerodynamic tip and higher BC. The TSX has been a winner for me and has been real effective on deer, Elk, and Antelope due to the penetration of these bullets which is in most cases were complete pass thru's but with heavy organ damage. All the bullets I recovered retained about 98% of their weight. I have not tried Hammers but I want to.
     
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  9. tooth doc

    tooth doc Well-Known Member

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    Have you tried different seating depths with barnes? I seat mine at least 20 thou of lands to as much as 120 thou. Has great effect on accuracy. I can usually get about .5 moa. My 375 rum is about .335 moa!
     
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  10. Highvoltage

    Highvoltage Well-Known Member

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    Personally I’d keep shooting the 150. I’ve killed elk to 480 yds with a 150 ttsx, complete pass through and a dead elk. Best wishes
     
  11. Coyote_Hunter

    Coyote_Hunter Well-Known Member

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    Lots of reasons why copper usually has lower B.C. values but that is not always the case.

    Given equal weight and profile, the copper bullet will be longer, requiring a faster twist to stabilize. Grooves on monos help reduce fouling but also reduce B.C. values. Additional length for copper may not be acceptable due to standard mag length limitations.
     
  12. tooth doc

    tooth doc Well-Known Member

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    Thats why i use barnes, never fail if i do my part. I have also found them very accurate, certainly enough for 600 yd shots with my least accurate rifle, under 1 in at 100. Usually .5 to .75 in at 100.