HMFIC of this Shit
Staff member
  • Apr 12, 2001
    Base of the Rockies
    By: Ted Hoeger (Jack Master)

    How long does it take to find our drop data for a target range?  If we need data quickly, most shooters are using some type of paper chart. This chart could be taped to the stock, on a data holder, or arm bar where with a quick glance we can read our data.  What if there is a faster way?  Welcome to the Speed Drop Factor.  Finding and using your Speed Drop Factor will allow you to memorize your drop data to a reasonable distance by remembering one number.

    Most rifle calibers have a portion of their bullet flight where the relationship between the drop of the bullet and distance traveled is consistent.  A zone where every 100yds of distance is an additional 1mil of elevation. As an example, if our data says 500yds = ~2.5mils, 600 = ~3.5mils, and 700 = ~4.5 mils we can start to see this consistent relationship between distance and come-up. For every 100 yards traveled the come-up is changing 1 mil.  As the bullet gets further away and starts to...

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    Shootin Stuff

    Sergeant of the Hide
    Full Member
    Feb 11, 2020
    This could be a game changer. When used with a fatal funnel or a spotter calling range, dialling elevation and making hits would happen extremely quickly with this method.

    If you need more precision, keep a correction card with your +- values for fine tuning on smaller targets. A correction card would also help you extend the usable Range of this method.

    You could even go one step further and work out the initial speed drop factor for your average density altitude and have another dope correction card for higher/lower density altitudes.

    Turret set to average DA SDF.
    Slip turret to +- density correction at the start of your shooting session or to the expected DA at location (monitor and adjust as needed)
    Range target,
    Dial yardage,
    Dial +- correction,
    Send it.

    Very, very cool stuff.