Crossbow Broadhead Tuning: Get Broadheads on Your Zero

You sighted in with the practice tips that came in the box, screwed on hunting heads a week before opening day, and the group moved three to six inches. That is the problem crossbow broadhead tuning solves. A field point is forgiving: it hides a slightly bent shaft or a crooked insert. A broadhead puts blades ahead of the bolt, and those blades magnify any wobble or misalignment into a miss.

The fix is a home procedure done in a set order, so you never adjust the scope to cover up a bolt problem. The steps below follow TenPoint's published tuning procedure and the general instructions in your crossbow manual, and they work whether you buy bolts from the crossbow bolts page or already own a quiver full.

Why Broadheads Hit Differently From Field Points

A field point is a smooth, pointed weight. Air flows around it cleanly, so a bolt that is slightly out of line still flies close to where you aim. Blades change that. Broadhead blades act like small wings at the front of the bolt, and when the bolt is even a little crooked those wings catch air and steer it. Bowhunters call this planing. A bent shaft, an insert that is not square to the shaft, or a head that sits off center all start the planing, and the blades finish it.

Fixed-blade broadheads are the most sensitive because their blades are exposed for the whole flight.

A mechanical broadhead keeps its blades closed until impact, so it usually flies closer to a field point, although a wobbling head or a weight mismatch still moves it. Our guide to fixed-blade broadheads explains which blade layouts catch the most air, which helps if you are choosing a head as well as tuning one.

Two more effects stack on top. A heavier head than the one you zeroed with changes the bolt's trajectory, so impact drops. And air drag on blades builds up over distance, so an offset you barely notice at 20 yards opens up at 40 and beyond.

One thing you will read in compound-bow tuning articles does not apply here. Paper tuning, moving an arrow rest and adjusting a nock point are vertical-bow fixes. A crossbow launches its bolt from a fixed rail, and TenPoint states plainly that paper tuning a fixed-blade broadhead shot from a crossbow is not an option. Tuning a crossbow for broadheads means tuning the bolts and heads, then the scope.

What You Need

• Your crossbow and its owner's manual, which lists the approved bolt length and minimum bolt weight.
• Bolts of identical brand, model and weight, with no mixed batches.
• Field points that weigh the same as your broadheads.
• The broadheads you will hunt with, plus the wrench or installation tool made for them.
• An arrow spinner, or a flat, smooth surface for a tip-spin check.
• O-rings sized for the broadhead's threaded base (the ferrule), if the head design uses them. TenPoint's procedure calls for a 6 mm outside, 4 mm inside diameter O-ring.
• A target rated for broadheads and a safe backstop.
• A fine marker and a notebook for numbering bolts and recording results.
• Optional: a grain scale to weigh bolts and heads.

Never dry-fire the crossbow while you work through this list. Releasing the string without a bolt can damage the limbs and string and injure you.

How to Tune Crossbow Broadheads, Step by Step

Work through the steps in order. Each one removes a variable before the next, and the scope stays untouched until step 9.

1. Confirm a solid field-point zero

Start from a reliable zero with field points that weigh the same as your broadheads. If you have not zeroed yet, or the field-point group itself wanders, our guide on how to sight in a crossbow scope walks through a 20-yard zero first. Tuning broadheads on top of a bad zero only hides the problem.

2. Check bolt spec and straightness

Make sure every bolt is the bolt length and weight your manual approves. Crossbow bolts are matched to the crossbow by the manufacturer's approved length and weight list, so treat spine as part of the bolt maker's spec rather than something you pick from a chart.

Our guide on how to choose crossbow bolts explains how length, weight and spine are selected.

Number each bolt with a marker near the nock. Spin each bare shaft on the spinner, or roll it on a flat surface, and watch for wobble. Bolt straightness is the maker's rated tolerance: the TenPoint Lighted Pro Elite 400, for example, is inspected to within .003 inch. A bolt that visibly wobbles is outside any rating, so retire it.

If several fail, our best crossbow bolts roundup compares replacement sets by straightness and weight.

3. Check the insert and the nock

Spin each bare bolt again and watch both ends. A wobble at the front means the insert is not square to the shaft. A nock that is cracked, chipped or loose goes in the bin, since a damaged nock can cause a dangerous misfire. If you use a lighted nock, confirm it is fully seated.

4. Install the broadhead

If your head design uses an O-ring, slip it onto the ferrule first. Thread the broadhead into the insert until it seats against the O-ring and insert. TenPoint recommends turning the bolt onto the head, held in its tool, rather than turning the head into the bolt, because your hand stays away from the blades.

5. Spin-test the assembled bolt

Spin the bolt with its broadhead on and watch the tip. A tuned bolt spins with the point still. If the tip wobbles, back the head out, re-seat it and spin again. Still wobbling? Move that head to a bolt that spun true in step 2. If the wobble follows the head, the head is the problem; if it stays with the bolt, the insert or shaft is.

6. Fixed blades only: align the blades with the vanes

TenPoint recommends a flat-surface check. Lay the assembled bolt on a table. The bottom two vanes and the bottom two blades should both touch the surface, and the bolt should not teeter. If they don't line up, tighten the head slightly and check again; the O-ring gives you a little room to turn it. Alignment does not fix a bent bolt, but it means every bolt in the quiver is assembled the same way, which helps them repeat.

7. Mechanicals: check retention and weight

Mechanical heads need less alignment work, but check that the blades are fully closed and the retention system holds them shut. Designs differ. The Ravin R102 Broadhead uses an internal spring clip, so it needs no lock ring or O-ring.

The TenPoint Nemesis Broadhead is a 100-grain four-blade head: two blades cut a 2-inch entry and two rear blades open after, for a rated 3.75-inch total cut. Both weigh 100 grains, so they pair with 100-grain field points. For most mechanicals, the spin test in step 5 is the main check.

8. Shoot field points and broadheads side by side

At 20 yards, shoot three field-point bolts at one aim point on your practice target, then three broadhead bolts at the same aim point on the broadhead target. Keep the crossbow level, since canting moves impact sideways and can be mistaken for a tuning problem. Compare the two groups' centers and their size.

9. Adjust the scope only for a tight, offset group

If the broadhead group is as tight as the field-point group but sits a little away from it, the bolts are tuned and the remaining offset is a sighting matter. Make fine windage and elevation adjustments, or note a separate broadhead aiming point (step 10 and the re-zero section below help you decide). If the broadhead group is spread out, the scope is not the answer: go back to steps 2 to 6 and find the bolt or head that is causing it.

10. Confirm at your longest planned distance

Drag and drop both grow with range, so confirm the broadhead group at the longest distance you plan to shoot. Our bolt drop chart shows how far your bolt should drop between 20 yards and that distance, so you know whether a low hit is expected drop or a tuning fault. Write the clicks, holds and bolt numbers in your notebook.

Weight Matching and FOC

Weight is the simplest cause to rule out and the easiest to get wrong. A 125-grain broadhead on a bolt zeroed with 100-grain field points makes the whole bolt heavier, so it leaves slower and drops more, and the group lands low. Match the head and the field point grain for grain, and weigh a few heads if you have a scale, because rated weights carry small tolerances.

Total bolt weight matters too. Your manual lists a minimum, and shooting under it can damage the crossbow. Heavier heads add weight safely; lighter ones can take you under the limit, so check before you switch.

Head weight also moves the bolt's balance point forward or back, which changes its FOC.

Our explainer on what is FOC covers why a more front-heavy bolt tends to fly steadier with broadheads.

Before you buy heavier heads, run the numbers in our FOC calculator so you see the new balance and total weight together.

Re-Zero or Hold Off? Deciding Your Hunting Zero

The rule is simple: hunt with a zero for the head you hunt with.

• Groups now agree: if field points and broadheads land together after tuning, keep one zero and practice with field points of the same weight.
• A consistent offset remains: if every check passes and broadheads still land a steady distance from field points, zero the scope for broadheads. Practice with broadheads into the broadhead target, or note the field-point offset in your notebook.
• The offset changes with distance: check each aiming point with broadheads out to your longest distance and record the holds.

Re-check the zero after any change of bolt, head, scope or mount, and before every season.

Common Mistakes

• Moving the scope to fix a wobbling bolt. The zero then fits one bad bolt and misses with the rest.
• Mixing bolt models or weights in one quiver, even from the same brand.
• Shooting broadheads into a field-point target. It wrecks the target and the blades, and pulling them out is unsafe.
• Ignoring one bad head. Number bolts and heads so a repeat flier shows up in your notes.
• Checking only at 20 yards. A broadhead offset can stay hidden until 40 yards.
• Hunting with dull or damaged blades after practice shots. Replace or sharpen them per the maker's instructions.
• Using a heavier head than your zero weight without re-checking.
• Letting the crossbow go untended. A dry rail or worn string changes how bolts leave it; our guide on how to maintain a crossbow covers the routine that helps it hold a zero.

Troubleshooting Table: Symptom, Cause, Fix

If your field points also miss in the same direction, the cause is not the broadhead. Our guide to crossbow shooting high or low diagnoses misses by direction and distance. If fixed blades still won't settle after every check, our best crossbow broadheads roundup compares mechanical and fixed heads that suit fast crossbows.

When to See a Pro Shop or Contact the Manufacturer

Some causes are not tuning problems. Take the crossbow to a pro shop, or contact the manufacturer, if:

• field points scatter too, even with matched, straight bolts;
• you see frayed strands or worn serving on the string or cables, which our guide to crossbow string serving damage helps you assess;
• the scope will not hold zero with tight mounts;
• bolts keep cracking or nocks keep breaking;
• you have warranty questions, which only the maker can answer.

Stop shooting at once if the limbs, cables or rail show cracks, chips or damage. A damaged crossbow can fail under load.

Bottom Line

Tune in this order: straight bolts, square inserts and sound nocks, heads that spin true, fixed blades aligned with the vanes, matched weight, and only then the scope. Confirm at your longest distance and write it down. If your current head never settles, a different design may suit your crossbow better. Broadhead rules such as minimum width vary by state, so check our guide to crossbow hunting laws by state and your state wildlife agency before you buy; this is not legal advice.