Can a muzzle brake interfere with a chronograph?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by DanielLudwig, Feb 8, 2011.

  1. DanielLudwig

    DanielLudwig Well-Known Member

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    Aug 18, 2005
    Just wondering, I worked up a load for my .300 Wby, and the velocity was on the high side of things, but i didnt question the chronograph, zero'd the rifle at 100yds, dialed up and moved out to 500, shot a very good group 1.5 MOA low! So now I am wondering if maybe my muzzle brake is messing with my data some way? I will lay it all out for you guys and see what you think.
    Custom .300 Wby, 28" Krieger brl.
    180gr Nosler BT
    88.5gr RL25
    OAL 3.751
    WLR-M primer
    4 shot average 3461 fps
    scope ht 2.90"
    BC .507
    zero- 100yds
    altitude- 1000ft
    500 yd come-up=4.96 MOA?
     
  2. backwoods83

    backwoods83 Well-Known Member

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    It will affect it if your chrony is to close to the muzzle, by that data your showing about 200fps faster than to be expected. With a 28" barrel and that bullet it should a compressed load of RE25 to get those speeds, pretty tightly compressed!
     

  3. DanielLudwig

    DanielLudwig Well-Known Member

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    Aug 18, 2005
    Believe it or not there is still room in the case! I think its mostly due to the fact that my rifle has a very long chamber which lets me load the 180s WAY out. Gonna try the chronograph again this weekend, might even try afew different ones and compare. How far away should I be setting it from the muzzle??
     
  4. backwoods83

    backwoods83 Well-Known Member

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    With a braked weatherby 20 feet at the closest, I wouldn't seat them any further out than having some of the bt below the neck/shoulder junction or right there at it.
     
  5. cowboy

    cowboy Well-Known Member

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    Agree with Backwoods: I use 20'0" from the muzzle of rifle to the center of screen on chrony and then go to a ballistics program and play with velocity at 20 ft. and get get my true muzzle velocity. Just as a side note - if you are using a folding open type chrony make sure it is fully open or you will get weird readings. I even use a small level and get chrony nuts on both ways.