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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

    “That is why there isn't an AK chart.” -SteyrAUG
    “They eat tide pods also so what's your point?” Retrorevolver77

  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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