Inclinometer on a Crossbow Scope: Angle Compensation

Crossbow Inclinometer in plain terms

Crossbow Inclinometer meaning: An inclinometer measures the up or down angle of a shot, so a rangefinding scope can show the horizontal distance and a corrected aim point.

Also called: angle compensation, angle-compensated distance, angle-compensated ranging

An inclinometer is a small electronic angle sensor. In a rangefinding scope or rangefinder it reads how far the shot points above or below level, and the device uses that angle to work out the horizontal distance to the target. That figure, often called the angle-compensated distance, is what the bolt actually has to fall over.

The reason it matters is gravity. Gravity pulls the bolt down across the horizontal distance, not along the straight line from your eye to the target. On a steep shot from a treestand the straight-line (line-of-sight) distance is longer than the horizontal one, so aiming for the laser's raw number tends to send the bolt high.

Some scopes go a step further than showing a corrected number. Burris says the Oracle X's integrated inclinometer factors the shot angle into the displayed aiming point, and Garmin lists angle-compensated distance among the Xero X1i's features alongside an electronic level.

Horizontal distance from a line-of-sight reading

Angle compensation on reviewed scopes

Facts below come from the manufacturers' product pages.

Why it matters

Most crossbow deer are shot from height or across uneven ground. The steeper the angle, the bigger the gap between the laser's straight-line number and the horizontal distance, and the more a raw reading overstates how far the bolt drops.

At typical stand heights and close ranges the gap is a yard or two, which matters little with a flat-shooting crossbow. It grows quickly with steeper angles and longer shots, where a slower bolt's trajectory curves more.

An inclinometer removes one estimate from a moment that already has plenty: you range, read one number and hold one aim point.

How to read it on a spec sheet

• Look for the words "angle compensation", "angle-compensated distance" or "inclinometer" on the spec sheet. A plain rangefinder without them shows line-of-sight distance only.
• Check whether the scope corrects only the displayed distance or also moves the aim point. Burris states the Oracle X adjusts the aiming point for angle.
• An electronic level or bubble level is a different feature: it shows canting (side-to-side tilt), not the up or down shot angle.
• If a scope lists no angle feature, assume it reads line of sight and practise steep shots at known distances.

Common mistakes

• Holding for the line-of-sight number on a steep downward shot and sending the bolt over the animal's back.
• Confusing an inclinometer with a cant indicator; one reads shot angle, the other reads tilt of the crossbow.
• Assuming every rangefinding scope compensates for angle without checking the maker's spec sheet.
• Forgetting that angle compensation corrects distance only; it cannot fix a scope that is not zeroed for your bolts.

Practising angled shots before the season

1. Set a target at a measured horizontal distance below a stand or a safe elevated platform.
2. Range it from the stand and note both the line-of-sight and the angle-compensated readings if your device shows them.
3. Shoot using the compensated number and check where the bolt lands.
4. Repeat at two or three distances so you know how much the angle changes your hold.
5. Always use a full-body harness and a haul line when practising from a stand.

See it in our reviews

• Burris Oracle X — rated 4.4/5
• Garmin Xero X1i — rated 4.3/5
• TenPoint Vision HD — rated 4.2/5