Berger 7mm BC's

Discussion in 'Reloading' started by Supertrucker, Mar 8, 2009.

  1. Supertrucker

    Supertrucker Well-Known Member

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    So what is the correct BC for the Berger 168's? It says .617 on the website and on the box, but I've heard it could be as high as .643 Berger was changing the BC's a while back.

    So what is the right one?
     

  2. royinidaho

    royinidaho Writers Guild

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    Here's my response and you're not going to like it......

    None of the above.

    .649 is on the old box. .617 is the new value based on more intensive work that Berger is doing.

    These values for for Joe run of the mill read the box value load, zero at a distance, run a computer program to develop a drop chart then go find stuff with hair on it.........

    For LRH purposes one of the published values can be used to get a start. Do wat Joe run of the mill does then go shoot at distances and work up your own drop chart for that bullet, powder, case, primer and rifle.

    You'll learn that several values will require tweaking:
    1) Line of site above line of bore.
    2) If you have a chrono then tweaking to get very low velocity spreads is required.
    3) If you don't have a chrono things take a bit longer.
    4) BC value. It'll change for various environmental conditions.
    5) BC value. It'll change with changes in elevation.

    Also it helps to do all of this shooting on flat ground. Not shooting up or shooting down.

    Once you get all of that done, you'll be able clearly state what the BC is of the bullet you are shooting with that specific load in that particular rifle.

    Hope that wasn't TMI.........:)

    If you are interested in comparing BCs for the sake of finding higher BCs, any thing over 0.6 is good. Around .7 is great. Over 0.76 is to die for.:D
     

  3. Supertrucker

    Supertrucker Well-Known Member

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    So in other words, run a drop chart with the Berger published BC and then go shoot and see how it compares and adjust as needed? That sounds like fun. My loads are within 27 fps of each other is this good?
     
  4. royinidaho

    royinidaho Writers Guild

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    You got it!!!

    Fun, you betcha!!!

    Do some computer runs with velocities 27fps apart and see if it fits your needs?

    Most shoot for the low teens.
    The really anal guys go for single digits. But hey, they are always killin' stuff a long ways off.

    I have a load for one rife (338 RUM) that gets me, on a consistent basis an extreme spread of 1. I think I died and went to heaven. It's pretty boring when a load like that is worked up but the confidence level goes into a much higher orbit.

    Good luck and have fun....