A sight tape is a non-linear distance scale attached to your sight's slider. You set your pin at a reference distance, then move the slider up or down for each yardage. The tape tells you where to position the slider for each distance without re-zeroing. Because arrow drop is not linear — it increases faster as distance grows — the marks on the tape are not evenly spaced either. The further out you go, the further apart the marks get.
Getting the tape right means accounting for your specific setup: arrow speed, arrow weight, sight radius, and your zero distance. A tape built for a 310 fps rig will not work on a 280 fps rig. A tape built with a 9-inch sight radius will be wrong on a 30-inch setup. Every variable shifts the spacing.
The arrow's path
The arrow does not travel in a straight line to the target. When you aim at a target 20 yards away, the bow is tilted slightly upward — just enough that the arrow's arc will intersect the line of sight at the zero distance. Before that, the arrow is rising above the line of sight. After, it falls below it.
For a typical adult compound bow shooting 270–300 fps with a 20-yard zero:
- The arrow crosses the line of sight on the way up at roughly 4–6 yards
- It peaks above the line of sight at roughly 13 yards — typically 1–2 inches above
- It crosses back through the line of sight at the zero distance
- From there it falls, and falls faster as distance grows
The 13-yard peak is why close-range shots at steeply angled 3D animals sometimes hit high — the arrow is still rising at that distance, and if you are shooting down at a significant angle, the arc shifts. The arc shape shown below uses 280 fps and a 20-yard zero.
The peak above LOS is small — roughly 1–2 inches for most adult setups. It is not a problem at close range because it is consistent and predictable. What it means for your tape is that the reference point (the zero distance) is not the maximum-height point on the arc. The arrow rises past the line of sight, peaks, and then returns. The tape only needs to account for the arc past the zero — the falling portion.
What shapes the tape
Arrow speed is the biggest single variable. Faster arrows drop less per yard. At 310 fps, the marks on your tape are closer together at long range compared to 280 fps — the drop between 60 and 70 yards is smaller, so the slider moves less between those marks. Speed comes from a chronograph, not from the bow's listed IBO rating, which is measured under test conditions your setup probably does not replicate exactly.
Arrow weight directly affects speed — heavier arrow, lower fps for the same bow, and that speed reduction is the main source of additional drop. In flight, the heavier arrow actually retains velocity better than a lighter arrow of the same diameter: aerodynamic drag force depends on the arrow's shape and cross-section, not its mass, so the same drag force acting on more mass produces less deceleration. The heavier arrow's better sectional density partially offsets the drop penalty from its slower departure. At practical archery distances the initial speed deficit still dominates, so the heavier arrow drops more — but the in-flight velocity retention works in the heavy arrow's favor, not against it.
Ballistic coefficient (BC) measures how efficiently an arrow retains speed in flight. A higher BC means less aerodynamic drag per unit of mass — the arrow holds its velocity better. BC matters most at long range. At 20 yards, the difference between a BC of 0.053 and 0.065 is negligible. At 80–100 yards, it produces a measurable shift in mark position. For hunting distances, BC differences between common hunting arrows are small enough to ignore. For 3D distances or field archery, they are worth accounting for.
Sight radius — the distance from the peep to the scope face — scales the entire tape. A longer sight radius means the scope sweeps more inches per degree of angular adjustment, which means the marks are spread further apart across the full tape. Two setups with identical trajectories but different sight radii produce tapes at different scales.
Height over arrow — the vertical distance from the arrow's centerline to the center of the peep — sets the zeroing geometry. A taller peep sits further above the arrow and requires a steeper downward sight angle to put the pin on target at any given distance. That angle shifts where the arrow's arc crosses the line of sight, which affects mark spacing across the full tape. A change of half an inch in peep height produces a noticeable shift in the tape, particularly at close and mid range.
Altitude and air density have a small but real effect at long range. At elevation, thinner air means less drag and slightly less speed loss per yard, compressing the long-range marks slightly compared to sea level. Most archers do not need to account for this unless they are shooting 3D in varied terrain at distances past 60 yards.
Why the marks are not evenly spaced
Arrow drop increases faster than distance. The drop from 60 to 70 yards is larger than the drop from 30 to 40 yards, even though both are 10-yard increments. The sight slider must compensate for that increasing drop, which means it must move more per 10-yard increment at distance. The marks on the tape get further apart as distance grows.
The effect is subtle across a 10-yard range but real. For a 280 fps arrow, 30-inch sight radius, 2.5-inch sight height, 20-yard zero:
| Distance | Mark position | 10-yd spacing |
|---|---|---|
| 20 yd (zero) | 0.000″ | — |
| 30 yd | 0.150″ | 0.150″ |
| 40 yd | 0.317″ | 0.167″ |
| 50 yd | 0.491″ | 0.174″ |
| 60 yd | 0.669″ | 0.178″ |
| 70 yd | 0.849″ | 0.180″ |
| 80 yd | 1.030″ | 0.181″ |
The 10-yard spacing grows from 0.150″ to 0.181″ across this range — a 21% difference. That is the non-linearity. On a printed tape at this scale, the gap between the 70-yard and 80-yard marks is visibly wider than the gap between the 20-yard and 30-yard marks. A tape printed with evenly spaced marks will be progressively wrong at distance.
Ballistic coefficients for common arrows
BC values for arrows are approximately stated in G1 equivalent terms. Actual in-flight performance depends on fletching size, point weight, and nock type. These are representative values for comparison — not datasheet figures.
| Arrow | Approx. BC (G1) |
|---|---|
| Easton Axis 5mm 300 | ≈ 0.060 |
| Gold Tip Pierce 400 | ≈ 0.053 |
| Victory VAP V6 350 | ≈ 0.065 |
| Carbon Express Maxima Red 350 | ≈ 0.056 |
BC differences in this range matter most past 60 yards. Within typical indoor or 3D distances under 50 yards, the spread between 0.053 and 0.065 produces less than an inch of difference at the target.
Building your tape
Two methods. The first is more accurate because it uses actual arrows from your actual setup. The second is faster if you have a reliable chronograph reading.
Method 1. Shoot in at known distances
Establish marks at your zero distance and at least two other known distances — ideally spaced 15–20 yards apart. Use a laser rangefinder on a flat range. Record where the slider sits for each confirmed distance. Then use the calculator to fit a curve through those three points and generate the full table for your complete distance range.
Three points give you a proper quadratic fit. Two points are usable but the extrapolated ends will carry more error. More points improve the fit.
Method 2. Ballistic calculator from chronograph
Measure your arrow speed with a chronograph. Enter that speed, your sight radius, your sight height above the arrow, and your zero distance. The calculator applies the ballistic model and produces a full table. This method is fast and accurate enough for most setups, but depends on your chronograph reading being representative of your actual shot-to-shot average — not a single outlier pass.
Open the sight tape calculator →