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Thread: MPBR Calculation with Suppressor

  1. #1
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    MPBR Calculation with Suppressor

    I have a 9inch 300AAC BLK SBR that I generally run with a suppressor. My question is not about the affect it has on the POI, I am aware that with/without it there will be some change. However, in the past, to calculate Maximum Point Blank Range, I would need velocity, BC and a calculator.

    For the 200gr SubSonic load for example, I know its velocity out of a 9 inch and its BC. If I want to zero my MPBR with the suppressor, I feel like it changes the inputs? The velocity change should be minimal right?

    Is it really that the MPBR is the same regardless, but the POI will be affected if I zero with or without the suppressor?

  2. #2
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    With a suppressor your velocity will increase, which should increase the MPBR.

    I dont know how much of an increase in velocity you will see though, a chronograph reading of suppressed vs unsuppressed would give you that data.

  3. #3
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    Quote Originally Posted by Randall View Post
    With a suppressor your velocity will increase, which should increase the MPBR.

    I dont know how much of an increase in velocity you will see though, a chronograph reading of suppressed vs unsuppressed would give you that data.
    Your ES will be many times larger than the velocity delta.

  4. #4
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    Good point. Could you not use the average of the suppressed vs unsuppressed clockings? Or would it still be too close? I’ve never messed around with a chrony, so my knowledge base is admittedly lacking.

  5. #5
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    Velocity increase that I (and others) have measured ranges from 0% to 1.4% with 5.56, so probably inconsequential. I have not measured any BLK, but I suspect that the POI shift will have nothing or little to do with velocity increase.
    RLTW
    “Your posts will be more accurate and received much better if you form your opinions with less emotion and more objectivity and then express them as if you’re in a discussion with friends, rather than an injured and cornered animal fighting for its life.” -Revolution 9 on the hide

  6. #6
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    Quote Originally Posted by 1168 View Post
    Velocity increase that I (and others) have measured ranges from 0% to 1.4% with 5.56, so probably inconsequential. I have not measured any BLK, but I suspect that the POI shift will have nothing or little to do with velocity increase.
    This.

    Plus subsonic load is a low pressure load. It is not going to see the same free-bore boost as a full power load.

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