To adjust a crossbow scope you do three separate things: turn the elevation and windage turrets to move point of impact onto the aiming point, set the speed dial to your bow's advertised FPS so the stacked yardage lines line up, and confirm each line on a target. Zeroing happens at 20 yards first.
That is the part people blur together. Moving the point of impact until the top line hits dead-on is zeroing, and the full step-by-step is covered in how to sight in a crossbow scope. This page is about the adjustments themselves - which dial controls what, how far a click moves the group, and why the speed ring matters more than most buyers realise.
The two turrets: elevation and windage
Under the caps on top and on the right side of the scope are two turrets. The top turret is elevation - it moves the group up and down. The side turret is windage - it moves the group left and right. On almost every crossbow scope the markings read UP/DOWN and L/R, and turning toward a direction moves the point of impact that way. If your group prints low and left at 20 yards, you turn elevation UP and windage R until it centres.
How far each click moves the group is the one number you must get from your own manual, not from a rifle habit. Many crossbow scopes move point of impact in coarser steps than rifle optics - commonly around one inch per click at 20 yards, sometimes more on budget models - and some have no clicks at all, just a friction dial you nudge. Count your clicks, shoot, and learn what one click does on your setup before you chase a group around the target.
Reading the stacked yardage lines
Most crossbow scopes are multi-line (sometimes called BDC) reticles rather than a single crosshair. The top line is your zero, set at 20 yards. Each line below is meant for a further distance - typically 30, 40, 50 and 60 yards, reading top to bottom. You do not adjust these lines with the turrets; they are fixed in the glass. What you adjust is whether they are telling the truth for your bow, and that is the speed dial's job.
Setting the speed dial so the lines are honest
Faster bows drop the bolt less between lines, so the gaps in the reticle have to stretch or shrink to match. Speed-adjustable scopes solve this with a ring on the body (Hawke, TenPoint and Excalibur all use a version of it). You rotate the ring to your bow's advertised speed - say 400 fps - and the yardage lines reposition to suit that trajectory. Get the right number from your crossbow's specs; the best crossbow scopes guide notes which models have a true speed dial and which only print fixed marks you have to verify yourself.
If your scope has no speed ring, the printed yardages are a starting point only. You set the top line at 20 yards, then shoot each lower line at its stated distance and note where it actually hits - the line labelled 40 might be your real 37 or 43. Those become your personal marks regardless of the number stamped beside them. Understanding how far the bolt is really travelling helps here, which is why how far a crossbow shoots is worth reading alongside this.
Adjusting a red dot or non-magnified sight
Red-dot and reflex sights have the same windage and elevation adjustments, usually as small slotted screws rather than capped turrets, and a brightness dial that is not an aiming adjustment at all. Single-dot sights have no built-in yardage compensation, so you either zero at one practical distance or learn your hold-over for longer shots. Multi-dot red dots work like the stacked-line scopes above: top dot at 20, lower dots verified by shooting.
| Adjustment | What it controls | When to touch it | How to confirm |
|---|---|---|---|
| Elevation turret | Point of impact up/down | Group prints high or low at 20 yds | Three-shot group centres vertically on the top line |
| Windage turret | Point of impact left/right | Group prints left or right at 20 yds | Group centres horizontally on the top line |
| Speed ring | Spacing of the lower yardage lines | Once, set to your bow's FPS | Each line hits dead-on at its stated distance |
| Brightness dial | Reticle visibility only | Light changes, dawn or dusk | Dot or lines readable, not aiming-related |
What resets your zero and forces a re-adjustment
A scope that was dead-on last season can print off this season without you touching a turret. The usual causes: a different bolt weight or a new broadhead (a 100-grain and a 125-grain head do not land in the same place), a restrung or re-timed bow, a scope that shifted in its mount, or rings that worked loose under the shock of the shot. Any time you change the bolt or broadhead you are shooting, re-confirm the 20-yard zero before you trust the lower lines. Matching your heads to your speed is covered in the bolt and broadhead guides.
Common adjustment mistakes
The ones that cost people an afternoon: adjusting off a single shot instead of a three-shot group, so you chase scatter that is really you and not the scope; turning the turret the wrong way because they assumed rifle-scope click values; setting the speed ring to a round number instead of the bow's actual tested speed; and tightening the mount after zeroing, which can nudge everything off again. Adjust off groups, confirm after every mount change, and write your real marks down.