Bare-shaft tuning a compound bow

Bare-shaft tuning compares two kinds of arrows shot at the same aim point: your normal fletched arrows, and arrows that are identical except that the vanes have been removed. You shoot a fletched group, then the bare shafts, usually from 15 to 20 yards, and read where the bare shafts land relative to the fletched group. The offset tells you how the arrow is leaving the bow.

Vanes steer an arrow. If it leaves the bow slightly sideways or tilted, the vanes pull the tail back into line within the first few yards, and the fletched group lands close to where you aimed. A bare shaft has nothing at the back to correct it. It keeps flying a little sideways and drifts toward the side its point was angled to at launch. The farther it flies, the bigger the gap between it and the fletched group.

That is why the test is more sensitive than paper. A paper tear records the arrow's attitude at one point a few feet from the bow, and the arrow can pass through the paper while it is still recovering from the launch, which hides small errors. A bare shaft shows the result of the launch over 20 yards with nothing correcting it. Rest, nock and spine errors small enough to leave a nearly clean tear can still separate a bare shaft from the fletched group.

What bare-shaft tuning does not tell you: whether your sight is set, whether your groups hold at 50 yards, or whether a particular broadhead is straight. It is a launch check, done with field points, that sits between paper tuning and broadhead tuning.

Paper tune first

Bare-shaft tuning refines a tune that is already close. Start with a clean or nearly clean tear at a few feet (the paper tuning guide covers it), with cam timing and cam lean set. If the bow needs yoke twists or cam shims, make those changes during the paper stage. At the bare-shaft stage, most adjustments should be small rest moves.

Check for contact

A vane brushing the rest, a cable or the riser pushes the fletched arrows off line, and the bare shaft, which has no vanes, won't show it. You end up measuring against a fletched group that is itself off. Spray foot powder or dry shampoo on the rest, the cables and the back of a fletched arrow, shoot it, and look for marks. Fix any contact before you compare.

Build bare shafts that match

The bare shafts must match your fletched arrows in everything except the vanes: same shaft model and spine, same cut length, same insert, same point weight, same nock. Strip the vanes and glue from one to three arrows. Then wrap tape on the shaft where the vanes were, and only there, until each bare shaft weighs the same as a fletched arrow on a grain scale. Tape anywhere else changes how the shaft flexes. Number every arrow so you can spot one that always lands apart.

Nocks

Use the same nock model and fit on every arrow, and check that each nock sits straight in the shaft. Nock rotation doesn't matter for vane clearance on a bare shaft, but a crooked or loose nock makes one arrow fly differently from the others. If one bare shaft keeps landing away from the others, rotate or replace its nock before you change anything on the bow.

How many arrows

Three fletched arrows and two or three bare shafts is a common setup. One bare shaft works, but with two or three you can see whether they agree with each other, which tells you whether you are reading the bow or your shot.

Distance

The test usually starts at 15 to 20 yards and is confirmed at 25 to 30. Close in, the bare shaft hasn't flown far enough for a small launch error to open a readable gap. Farther back the gap is bigger and easier to measure, but form errors grow with it, and a bare shaft that is well off early in the process can miss a small target. Start where you shoot tight fletched groups, get the bare shafts close, then step back for a finer read.

Target and safety

Use a large target with plenty of room around the aim point and a backstop you trust. Bare shafts get field points only. Never put a broadhead on an unfletched arrow; its flight is extremely erratic and dangerous.

Shoot indoors or in calm air. Use your hunting anchor, grip and release, and the same sight pin for every arrow.

1. Shoot three fletched arrows at one aim point. If they don't group, stop: the test needs a fletched group to measure against.
2. Shoot the bare shafts at the same aim point with the same pin. Don't change your hold to help them.
3. Note where the bare shafts land relative to the center of the fletched group: up or down, left or right, and how far.
4. Pull the arrows and repeat the round at least once. Change something only when the bare shafts land in the same place round after round.

Bare shafts are less forgiving than fletched arrows. A small pluck, some grip torque or a punched release that the vanes would correct on a fletched arrow shows up on a bare shaft. Keep the bow hand relaxed and let the shot break on its own. When you get tired or your form starts to slip, stop for the day. Readings taken then point to problems the bow doesn't have.

Read the bare shafts against the center of the fletched group, not against the aim point. The patterns below are written for a right-handed archer shooting a release aid. For a left-handed archer, up and down read the same, and left and right flip.

One rule covers most of it: a bare shaft drifts toward the side its point was angled to as it left the bow, which is the opposite of the side the tail kicked. A bare shaft that hits right left the bow with its tail kicked left. A bare shaft that hits high left the bow tail-low.

Severity, roughly (at 20 yards)

• About 1/2 inch or less: as close as a careful tune gets. Leave it.
• Within about a baseball's width: good enough for most hunting setups. One or two small rest moves may close it.
• Several inches that rest moves don't close: stop moving the rest and look at cam lean and spine. For finger shooters, a gap of more than 6 inches at 20 yards means the arrow has to change.

Vertical: nock point or rest height

Bare shafts high → raise the nock point or lower the rest. Bare shafts low → lower the nock point or raise the rest. Both moves change the same thing, the height of the nock relative to the rest, so change one at a time. Steps of 1/32 inch are typical.

If the bare shafts don't respond to nock changes, or the vertical gap changes from one session to the next, have the cam timing checked. The cam timing guide explains what to look for.

Horizontal: move the rest toward the bare shafts

Bare shafts right → move the rest right, toward the riser. Bare shafts left → move the rest left, away from the riser. Use 1/32-inch moves, and smaller ones (1/64 inch) as the gap closes.

This is the reverse of the vertical rule, where the rest moves away from the bare shafts. Don't carry the rule for one plane over to the other. Shoot a full round after every move.

When the rest runs out: cam lean

Rest moves at this stage should stay small. If the rest has moved well away from the bow maker's centershot setting and the bare shafts still sit to one side, the rest is compensating for something else, most often cam lean. Correct it with the bow's own system: yoke twists on yoked bows, cam shims or spacers on others, following the manufacturer's procedure.

The cams move the opposite way to the rest, because shifting the cams (and the string) left does the same thing as moving the rest right. Bare shafts right on a right-handed bow call for shifting the cams left; bare shafts left call for shifting them right.

Spine

When rest and cam changes don't close a horizontal gap, the arrow's dynamic spine doesn't suit the bow. For a right-handed archer, bare shafts that stay right are weak and bare shafts that stay left are stiff.

• Weak (bare shafts right, RH): a lighter point, a shorter arrow (1/4 inch at a time), a stiffer shaft, or less draw weight.
• Stiff (bare shafts left, RH): a heavier point, a longer arrow, a weaker shaft, or more draw weight.

Point weight is the easiest change to test, because you can swap points without cutting anything. If a lighter point moves the bare shafts left toward the group, the arrow was weak. Before you cut arrows or buy new shafts, check that your shaft is a sensible match for your draw weight, arrow length and point weight with the arrow spine chart. The arrow setup guide covers spine, point weight and FOC together. Any change to point weight or length also changes where the arrow hits, so re-check your sight afterward.

• Skipping the paper tune and contact check. Bare shafts then measure against a fletched group that is itself off.
• Bare shafts that don't match the fletched arrows: a different point, a missing insert, no tape to replace the vane weight.
• Wrapping the replacement tape along the whole shaft instead of where the vanes were.
• Changing the bow after one round. Repeat the round and act only on a pattern that holds.
• Moving the rest and the nock at the same time.
• Using the vertical rule for horizontal, or the reverse. The rest moves away from high or low bare shafts and toward left or right ones.
• Pushing the rest far off centershot to force a match instead of correcting cam lean or spine.
• Starting at 30 yards or more before the bare shafts land close at 20.
• Reading the bow through tired or inconsistent form. Bare shafts show release and grip errors that fletched arrows hide.
• Putting a broadhead on a bare shaft. Never do this.

Paper and bare shafts read the same launch from different distances, so they usually agree. For a right-handed archer, a tail-left tear and a bare shaft right of the fletched group are the same error, and a tail-low tear and a bare shaft high of the group are the same error. When the two disagree, the disagreement is useful.

Clean paper, bare shafts off

This is common, and it is the reason to run the test. Paper reads the arrow a few feet from the bow and can catch it while it is still recovering from the launch. Trust the bare shafts at 20 yards and make small rest moves.

Bare shafts on, fletched arrows tearing

If bare shafts land with the fletched group but fletched arrows tear the paper, look for vane contact. Shooting a bare shaft through paper at close range shows the same thing: if the bare shaft makes a clean hole and a fletched arrow doesn't, the vanes are hitting the rest, the cables or the riser.

The two point in different directions

If paper says one thing and the bare shafts say another, one of the readings is wrong. Re-check for contact, shoot both tests again with attention on your form, and change nothing until both readings repeat.

Bare shafts through paper

A close-range variant: shoot a bare shaft through paper from about 6 feet and read the tear as you would a fletched tear. Some tuners then step back a few yards at a time until the bare shaft makes a clean hole at 20 yards. It shows the launch with no vanes involved, and it saves arrows early on, when bare shafts may land far from the group.

Broadhead tuning

A bare shaft and a fixed-blade broadhead both expose launch errors that vanes hide on a field-point arrow, and a bow whose bare shafts group with its fletched arrows usually needs little extra work to fly broadheads. It still needs the check. The broadhead tuning guide covers confirming that the heads you will hunt with, spun and weight matched, hit with your field points.

Walkback tuning

Walkback tuning uses fletched arrows at increasing distances against a vertical line to check rest position over range. It catches small centershot errors that don't show at 20 yards. Many tuners do it after bare shafts and before broadheads; the walkback tuning guide walks through it.

Standard order

Contact check → paper → bare shaft → walkback → nock tuning → broadhead → groups.

The compound bow tuning guide puts every step in that order on one page.

Do I have to bare-shaft tune a compound bow?

No. Paper tuning is the most common test for compound shooters using a release. Bare-shaft tuning is a finer check that is most useful if you hunt with fixed-blade broadheads or your arrow is near the edge of the right spine. If your form isn't consistent yet, bare-shaft readings will be noisy; for that reason, most average bowhunters can skip it.

How far away should I shoot bare shafts?

Start at 15 to 20 yards. Once the bare shafts land with the fletched group there, check again at 25 to 30 yards. Farther back the gap is larger and easier to read, but form errors grow too, and early in the process a bare shaft can land well away from the group.

How many bare shafts do I need?

One to three, shot after a group of three fletched arrows. With two or three you can see whether the bare shafts agree with each other. If they don't, you are reading your shot or your arrows, not the bow.

My bare shaft hits right of my fletched arrows. What does that mean?

For a right-handed archer, the arrow is leaving the bow with its tail kicked left and its point angled right. Move the rest right, toward the riser, in 1/32-inch steps. If small rest moves don't close the gap, correct cam lean, then treat it as a weak arrow: a lighter point, a shorter arrow or a stiffer shaft.

Do the directions flip for left-handed archers?

Left and right flip; up and down don't. For a left-handed archer, a bare shaft that hits left is the weak-arrow case, and the rest moves left, toward the riser. A bare shaft that hits high means the nock point is low for both.

Can I shoot a bare shaft with a broadhead on it?

No. Never put a broadhead on an unfletched arrow: its flight is extremely erratic and dangerous. Bare shafts get field points matched in weight to your broadheads.

How close do the bare shafts need to land to the fletched group?

A careful tune puts them within about 1/2 inch at 20 yards. Within about a baseball's width is good enough for most hunting setups. If they are several inches off and small rest moves don't help, stop moving the rest and look at cam lean and spine.

Should I weight-match the bare shafts?

Yes. Vanes and glue add weight at the back of the arrow, and a lighter arrow flies differently. Wrap tape on the shaft where the vanes were, and only there, until each bare shaft matches a fletched arrow on a grain scale. Tape elsewhere on the shaft changes how the arrow flexes.

My bare shafts land all over the place. Is the bow out of tune?

Not necessarily. If the bare shafts don't group with each other, there is no offset to read and no bow adjustment will fix it. Bare shafts are less forgiving of grip and release errors than fletched arrows, so check your shot first. Then check the arrows: a bent shaft, a crooked nock or a bare shaft that weighs more or less than the others will fly apart from the rest.

Is shooting a bare shaft through paper the same test?

It is a close-range version. Shoot a bare shaft through paper from about 6 feet and read the tear like a fletched tear. Some tuners step back a few yards at a time until the bare shaft makes a clean hole at 20 yards. If a bare shaft makes a clean hole and a fletched arrow doesn't, the vanes are hitting something.

Bare shaft

An arrow identical to your fletched arrows except that the vanes have been removed, with tape where the vanes were to match their weight.

Fletched group

The group of normal arrows the bare shafts are measured against. Read the offset from its center, not from the aim point.

Tail kick

The sideways or vertical angle of the back of the arrow as it leaves the bow. A bare shaft drifts the opposite way to the kick.

Porpoising

Up-and-down tail motion in flight caused by a nock point that is too high or too low. Shows as bare shafts high or low of the group.

Fishtailing

Side-to-side tail motion in flight. Shows as bare shafts left or right of the group.

Nock point

Where the arrow nock sits on the string, set by the d-loop on most compounds. Sets the arrow's height relative to the rest.

Centershot

The arrow's side-to-side position relative to the string's path. Each bow maker publishes a starting value.

Cam lean

Sideways tilt of the cams at full draw, caused by uneven cable tension. Corrected with yoke twists or cam shims.

Dynamic spine

How much the arrow actually flexes when shot, given its static spine, length, point weight and your draw weight.