jbmballistics

  1. rustyinbend

    BC Advice - Published vs Calculated vs Custom Drag Curve ???

    What's the conventional wisdom out there regarding the BC to plug into a Kestrel? The choices I'm looking at are: The number on the bullet box published by the manufacturer The number calculated by the JBM Ballistics Calculator using actual down-range velocity from my Labradar The number that...
  2. D

    Rifle Scopes Change scope zero with altitude change

    Bullets are hitting the bullseye at 200 yards at altitude of 5,500 feet. Scope elevation knob is set to zero. If I do not change the scope elevation knob; then, bullets will hit some unknown distance below the bullseye at 200 yards at altitude of 3,000 feet. How many MOA do I need to turn...