1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

Published Velocities

Discussion in 'Shooting Related Threads' started by FNG, Jul 15, 2009.

Thread Status:
Not open for further replies.
  1. FNG

    FNG Member

    Joined:
    May 5, 2008
    Messages:
    175
    For those of you who have cronographed your reloads, do you find that actual velocities are generally greater than, equal to, or less than the velocities published in the loading data ? I don't have the ability to chronograph my loads and I'm trying to get some idea how close the published data is to actual performance (assume no huge ambient temperature extremes) If it makes any difference, I'm specifically interested in Green Dot and Clay Dot loads using older style AA hulls, Win. 209 primers and CB1100-12 wads with 1oz. #8 shot. Thanks for your inputs.
     
  2. goatskin

    goatskin TS Member

    Joined:
    Jun 24, 2009
    Messages:
    1,781
    Without commenting on your load/components, most people who have 'consumer' chronos (and then have their loads SAAMI tested by DR, PR, TA, etc.) find their readings are +30 fps FASTER than that of the induction machines.

    *EYE* have found that +30fps to be pretty constant & consistent from velocities of 1100-1700dps of various kinds of shot that I have had tested after I had logged them on my gizmos.

    It goes w/o saying that the more consistent and repeatable YOUR set-up is, the better, more believable data you'll get from any consumer box.

    Bob
     
  3. Trap2

    Trap2 Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    3,685
    Location:
    Redding, California
    FNG... I have chronographed many loads and have found them to all be slightly faster than the published information. They included the Green Dot loads you mentioned above. It is my understanding that published loads are measured out of a 30" shotgun barrel. It seems as the longer barrel increases the velocity somewhat. Dick Bennett explains this finding in his book "Trapshooting is a Book of Opposites". His theory, as I recall without the book at hand, is the speed increases about 10fps for each additional inch of barrel length, up to a certain point.... Dan Thome (Trap2)
     
  4. timb99

    timb99 Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    7,330
    Location:
    Shawnee, Kansas, USA
    Interesting.

    When I sent some reloads to Kevin Lewis to have him test them, the velocities came out slower than what the published data indicated.

    Book said 1180. Tests said 1160.
     
  5. Chip Pitcairn

    Chip Pitcairn TS Member

    Joined:
    Jan 29, 1998
    Messages:
    75
    The velocity of the large mass is measured at the factory. Our chronos measure the first pellets. Different machines. Factory results should be closer to real world shot column velocity,all other variables being equal.
     
  6. 6878mm

    6878mm Member

    Joined:
    Jan 29, 1998
    Messages:
    160
    Are velocities measured @ the muzzle or a small distance from the muzzle??
    3ft or so?
    I mean for the factory loads??
     
  7. Neil Winston

    Neil Winston Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    7,848
    The first electronic screen is 18 inches from the muzzle, the second is 54 inches, so the average is 36 inches, three feet.

    That closer than I can generally make a light-operated chronograph work, where five or six feet is more like it,

    The speed are dependent on the choke used and so are variably different from published speeds, as is the lot of powder you used, the primer, and the way you put them together, Even if you use an industry chronograph, you speed will be different, sometimes a lot, sometimes less, sometimes more, sometimes less.

    Neil
     
Thread Status:
Not open for further replies.