Factory Ammo Velocities and Guessing Ballistics

Discussion in 'Long Range Hunting & Shooting' started by snookntarpon, Feb 28, 2011.

  1. snookntarpon

    snookntarpon Well-Known Member

    Messages:
    128
    Joined:
    Feb 28, 2011
    I have an A blot Stainless stalker that shoots .32" 5 shot groups at 100. Locally we have no long range shooting clubs or even places to shoot. barrel length 26"

    Looking to get an MOA reticle or turret installed on my VariX3, but need to know actual speed. so i am buying a chrono.

    shooting federal 7mm rem mag 160g barnes x triple shock factory ammo that the rifle loves.

    Is it safe to calculate ballistics off of software using the muzzle speed or do i need to travel 4 hours to shoot at a mere 300 yds to then guess what the drop will be out to 600?

    It will all in the end be a guessing game until I get out somewhere long range.Any guidelines I can use to get accurate ballistics from shooting 100 yd range? what kind of speed can i expect from this compared to posted speeds?

    Thanks and sorry if this has been asked before.gun)
     
  2. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Going off a chronograph will probably give you a better idea than even shooting just to 300 yds.

    IMO, If you want to figure velocity from actual shooting point of impact, it needs to be out to about 400 minimum, 500 would be better. There are alot of variables in point of impact, and an important one is the sight height and true exact sight in distance. Alot of this is "masked" when shooting under 300 yds.

    FWIW, I would chrono the loads. Then when you get a chance to shoot long range, compare the computer predicted ballistics with real life ballistics. IMO, real life ballistics are the way to go, but I realize not everyone has the ability to shoot long range very easily.
     

  3. Dr. Vette

    Dr. Vette Well-Known Member

    Messages:
    2,032
    Joined:
    Dec 30, 2009
    I'll throw in a "it depends."

    Using published data from Hornady, the ammo for my 7mm Wby Mag shoots exactly where it is predicted to hit in two different rifles, even out to 500 yards.

    However, I'm not going to guarantee the same is true for your rifle. Odds are that the BC of the bullet will be right on, but using a chrono will give you true MV, which is where most of the published error seems to occur.

    Hope that helps.