The distance is 450 yards well within the ethical range of an accomplished rifleman with a precision rifle. Taking the concept to drastic lengths, let's consider the sort of uphill or downhill shot occasionally encountered by mountain goat and bighorn sheep hunters, and even desert- or alpine-country mule deer hunters: Imagine the animal you're after has bedded at the base of a massive cliff for the day, and you spent the morning hiking around and getting above it. It takes time, but using a smart-phone ballistic app is an exceptionally accurate way of calculating precise bullet impact, especially as angles become extremely acute. Between 520 yards and 600 yards the point of impact differs about 25 inches-way more than acceptable with an on-target hold. A calculation (600 yards multiplied by 0.87) shows the shoot-to distance as 522 yards. 30-06 load, taken at the same 30-degree angle. Although very long shots are rarely taken at acute angles, for the sake of argument, let's consider a 600-yard shot with that same. You'll be just fine holding center on vitals, even at that quite-steep 30-degree angle.Īs distance increases, angle becomes far more critical. 30-06 load pushing a 165-grain Nosler Ballistic Tip bullet impacts fractionally more than three inches of difference between 260 and 300 yards. Consider this: If you're taking a shot on a mule deer with a 10-inch vital zone on a ridge, at a 30-degree angle above you, a quick calculation (300 multiplied by the 30-degree cosine percentage 0.87) will show you that your shoot-to distance is 261 yards.Ī common. Inside of 300 yards, you've got to be at a really steep angle before you need to worry about it at all. Here's a chart, courtesy of the SAAM shooting school at the FTW ranch, showing angle cosine/actual-distance percentages: Angle/Degree to Cosine Multiplierĭegree of angle - Multiplier of Measured YardsĪs distance increases, the effect of angle becomes dramatically more pronounced.Īs you can see, until angles get quite acute, bullet point of impact isn't affected all that much. 64, and you get a shoot-to distance of 552 yards. More math is required for most distances: for example, if your rangefinder reads 862 yards and the angle 50 degrees (cosine 0.64), unless you're a math wizard you'll have to dig out the calculator. Hold for 940 yards, or 94 percent of the actual distance, and shoot. Keeping it simple, let's say that your shot distance is 1,000 yards.
Using a rangefinder that calculates true ballistic range (TBR) such as this specialized binocular is the simplest, fastest way to determine what range to hold in order to compensate for shot angle and accomplish accurate bullet placement. Once calculated, dial your scope or hold over for the horizontal distance, and assuming an accurate rifle and correct shot execution, you'll hit your target.
If you're good at math (which I'm not) you can run a simple calculation based on the cosine of the angle (which you've measured) and the distance (which a rangefinder provides) and work out the horizontal distance to your target. True Ballistic Distance (TBR)Ī very simple way of doing this is to calculate the "true ballistic range," which is the horizontal distance between you and the target. Once you've measured the angle, you've got to calculate how much that angle will affect your bullets' point of impact. We'll take a closer look at various angle-estimating tools shortly. Angle can be measured many ways, ranging from scope-mounted gadgets, to smart-phone apps, to laser rangefinders that measure and display it. As precision rifles, optics, laser rangefinders, and other tools have increased the viable range of skilled riflemen, understanding of compensating for angles has increased, as have the tools necessary for accurately doing so.Ĭompensating when shooting downhill and uphill is a science, not voodoo, but you've got to have an accurate read on the angle for your compensation to be accurate.
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