Front-of-Center Testing Overview

Overview

The 2026 Front-of-Center study evaluates how front-of-center percentage interacts with arrow grouping and torque-induced drift. Each build in the matrix is shot under four conditions: untorqued field point, untorqued QAD Exodus fixed-blade broadhead, torqued field point, and torqued QAD Exodus broadhead. The next section lays out the build matrix and explains why a matrix design rather than a simple front-of-center sweep was used.

The regression, confidence-interval, scatter, and slow-motion plots that summarize this dataset live in the Front-of-Center plots section; the underlying tables (build details, build weights, front-of-center measurements, insert specs, measured static spine, radar shots, shot-group summary, shot coordinates, and derived analysis tables) live in the data section.

This page focuses on what was physically built, measured, and shot. The companion methods pages cover why FoC is hard to test in isolation, how the matrix was analyzed in post-processing, and the technical analysis appendix.

A Note On Spine Numbers

In this study, "spine" means the manufacturer spine label. "Measured static spine" means the deflection of the shaft under a standard load.

• Lower spine number = stiffer shaft. Spine 200 is stiffer than 250, 300, or 340.
• Higher measured deflection = weaker shaft.A deflection of 0.300" is weaker than 0.200".

Build Matrix

What Was Tested

The matrix spans four shaft spines (340, 300, 250, 200) on two shaft models (Easton 5.0 and Easton 5mm FMJ Max), with total up-front mass iterated across the matrix from 125 to 350 grains. Critically, mass was iterated using Gold Tip FACT weights stacked inside the shaft, not by swapping different external points: across the primary matrix every build flies with an identical 100-grain QAD Exodus fixed-blade broadhead or 100-grain field point on the nose, so external tip geometry is held constant. Total up-front mass is varied entirely by the FACT-weight stack screwed into the shaft behind the insert.

The resulting builds span 11.2% to 29.7% front-of-center. Per-build particulars (shaft, spine, length, internal weight stack, total mass, FoC%) are tabulated in the Front-of-Center Build Details table.

The matrix at a glance, with total up-front mass (grains) on the rows and shaft spine on the columns. Each cell lists which shaft model(s) carry a build at that combination: 5 for Easton 5.0, M for Easton 5mm FMJ Max.

Empty cells are combinations not present in the 2026 dataset. The 270 gr (Easton 5.0, 200 spine) and 280 gr (FMJ Max, 200 spine) rows are intermediate points that were added to create exact weight matches between the 5.0 and FMJ Max builds.

One additional build extends the matrix at the high-front-of-center end: an Easton 5.0 / 340 spine build run with a heavier 300-grain external point (plus 50 gr internal FACT weight, 350 gr total up-front), reaching the maximum measured 29.7% FoC. This build deliberately breaks the constant-100 gr-tip constraint to push FoC past what the FACT-weight stack alone can reach on a stiff 340 shaft. It is excluded from the primary analysis so every analyzed build flies the same 100-grain tip; the data still lives in the public data tables for reference.

Why a Matrix Design

Front-of-center percentage cannot be isolated as a single experimental variable. Increasing up-front mass to push FoC up also increases total arrow mass (and therefore lowers launch velocity), and the heavier point alters the arrow’s dynamic spine reaction. Two paths are open: (a) try to hold every other variable constant while moving FoC, which is physically impossible because FoC is by construction a function of mass distribution; or (b) span the joint space of spine, shaft, and up-front mass, and look for trends across the resulting matrix of builds.

The 2026 design takes path (b). The Front-of-Center scatter plots page is organized around this premise: each metric is plotted against FoC%, total weight, spine, and launch velocity in turn, and color-coded scatter plots let the reader see how an effect attributed to “FoC” co-varies with weight or spine.

The one confound the design does hold constant is external arrow tip geometry: across the primary matrix every build flies with the same 100-grain QAD Exodus broadhead or 100-grain field-point profile on the nose, so aerodynamic-drag and impact-mechanics differences between builds are attributable to spine, total mass, or mass distribution rather than tip shape. The single 300-grain-point extension at 29.7% FoC is the only build that breaks this constraint and should be read with that caveat in mind.

Measured Static Spine

Every shaft family and spine grade in the matrix has its actual static spine measured: the deflection of the shaft over a 26-inch span under a standard 1.94 lb load, in inches.

Two shafts that share a label can differ in measured deflection, and the relationship between label and deflection is not the same across shaft families. The spine report uses the measured 26-inch deflection in place of the label as a sensitivity check; both views give qualitatively the same result.

Per-shaft measurements live in the Measured Static Spine table.

Insert-Spec Measurements

For every insert / FACT-weight stack in the matrix, two properties are measured on the bench:

• Insert length inside the shaft. How far the stack extends back from the front of the shaft.
• Insert balance point from the shaft end. The center of mass of the stack, measured back from the front of the shaft.

Adding internal mass changes more than total weight. Where the mass sits, and how far back the stack extends, can affect how the shaft bends and recovers. Measuring both length and balance lets the analysis look for an independent effect beyond raw insert weight.

This matrix could not separate insert geometry from insert mass: insert weight, length, and balance point are tightly correlated across the inserts available. The diagnostic is included as a caveat, not a standalone claim. See the analysis appendix for how this was handled.

Per-insert measurements live in the Insert Specs table.

Pre-Test Nock Tuning

Every arrow used in the 2026 Front-of-Center study was nock-tuned before being fletched. The procedure: at Easton Archery’s lab, prior to the testing days, each bareshaft was shot through paper while iterating nock rotation until the arrow produced a bullet hole. The resulting nock orientation was then marked on the shaft, and the arrow was fletched in that exact orientation.

Nock tuning per arrow is independent of the per-build XTS retune that happens during testing (step 2 of the shooting protocol below). The nock tune fixes the arrow’s clocking relative to its own fletching; the XTS retune fixes the bow’s launch behavior to the build currently mounted on it. Both are required for the torqued-vs-untorqued comparison to be meaningful.

Test Equipment

The 2026 Front-of-Center test was run at the same facility, target distance, photo-capture rig, and pulley torque magnitude as the restorative-lift component test; only the bow tuning workflow differs (per-build XTS retune, called out in the protocol below).

• Bow: Hoyt AX-3 33 at 28″ draw length, 70 lb draw weight, retuned per build via Hoyt’s XTS tuning system (see protocol step 2).
• Indoor facility: Easton Salt Lake Archery Center, Salt Lake City, UT. Same controlled indoor environment used for the component-test restorative-lift protocol.
• Target distance: 70 yd, matching the restorative-lift protocol.
• Pulley torque system: same hardware and same applied magnitude as the restorative-lift test. A 1.25 lb weight hangs through a pulley and pulls horizontally on the bow at a point 6″ from the stabilizer bushing, rotating the bow roughly 2° and producing a paper tear of approximately 1″ nock-right at 15 ft. Every torqued shot in the 2026 Front-of-Center protocol sees the same induced launch error, so torque-induced drift can be compared cleanly across builds.
• Photo capture: Panasonic Lumix S5IIX with a 70 mm lens, mounted in a consistent position relative to the target between sessions. Each frame includes the floor / tape / pin / background reference annotations described on Photo Capture & Analysis, which is the canonical source for how each impact photograph is converted into the (x, y) coordinates and 95% t-distribution confidence intervals used here.

Per-Build Shooting Protocol

The same seven-step sequence is run for every build in the matrix:

1. Prepare the spine + up-front-mass combination arrow builds.
2. Tune to bullet holes via Hoyt’s XTS tuning system. Each build is individually retuned before its torqued comparison runs. Combined with the per-arrow nock tune done before fletching, this is the methodological hinge that makes the torqued-vs-untorqued comparison fair: a drift attributed to torque on a poorly-tuned build would be confounded by the launch error already present in the untorqued case, so every build starts from a tuned baseline (both at the arrow level and at the bow level).
3. Shoot 6 field points untorqued; photograph as one group.
4. Shoot 6 QAD Exodus broadheads untorqued; photograph in two groups of 3 to limit broadhead breakage from arrow-on-arrow impacts. The 6 arrows are pooled into a single logical group of n = 6 for downstream statistics.
5. Apply lateral torque via the pulley system (see apparatus above).
6. Shoot 6 field points torqued; photograph as one group.
7. Shoot 6 QAD Exodus broadheads torqued; photograph in two groups of 3 (same broadhead-breakage precaution as step 4). Pooled to n = 6 for statistics.

Every build therefore contributes four shot groups (untorqued field point, untorqued broadhead, torqued field point, torqued broadhead) at n = 6 per group, plus the radar capture of launch velocity that the plots page joins back in.

What Ends Up on the Plots

Per build, the protocol produces two families of reportable surfaces:

• Group statistics (mean radius, group size as extreme spread, pairwise spacing) under each of the four conditions: untorqued field point, untorqued broadhead, torqued field point, torqued broadhead.
• Lateral drifts derived from the four group means: torque-induced drift on the field-point group (torqued FP vs. untorqued FP), torque-induced drift on the broadhead group (torqued BH vs. untorqued BH), and field-point- vs-broadhead drift in both the untorqued and torqued conditions.

The math behind every metric (centroid, mean radius, group size, pairwise spacing, inter-group lateral drift, and 95% t-distribution confidence intervals at small n) lives on Photo Capture & Analysis. That page is the canonical source; this page does not re-derive the formulas.

Per the build-matrix framing in the second section, each resulting metric is plotted against multiple x-axes (FoC%, total weight, spine, and launch velocity) on the Front-of-Center scatter plots page, and color-coded scatter plots layer in a second build-attribute axis on top of that. The intent is that the confounded variables (FoC%, total mass, dynamic spine, and launch velocity) can be inspected jointly across the matrix rather than assumed away.

Torque KPI Construction

Two of the torque-related KPIs are not simple measurements off a single group, so they get a short construction note.

Broadhead Extra Drift Past Field Point

The lateral position of the torqued broadhead group is compared against the torqued field-point group on the same build. The difference, in inches, is how much farther the broadhead drifted than the field point did under the same applied torque. Positive values mean the broadhead moved farther.

Broadhead Distance From Synthetic Aim

The torqued broadhead group is compared against a synthetic aim point: the untorqued field-point centroid plus 18 inches laterally. That point is where the bow is pointing after the torque jig rotates the riser, so it stands in for where a cleanly-launching arrow would land at 70 yards under the same torque. The difference between that aim point and the torqued broadhead centroid is the KPI.

The 18-inch offset is fixed by the geometry of the pulley torque setup (Test Equipment above) and the 70-yard target distance. It is the same constant for every build, so the KPI is still a fair across-build comparison.

KPI Definitions

The analysis reports use a small number of KPIs, all in inches, all with "lower is better." In plain language:

The same definitions live, in machine-readable form, in the KPI Definitions data table.

Early-Flight Behavior with Slow-Motion Video

The build matrix, KPIs, and shot protocol above all live in the same physical test: groups of arrows shot at 70 yards, torqued and untorqued, measured from impact photos. On top of that, a subset of the FoC builds were filmed with a Phantom high-speed camera so we could measure what each arrow was actually doing in the first 45 feet of flight.

The camera was placed overhead at successive distances from the bow, capturing three torqued and three untorqued shots per build at each station. Every frame is processed to recover the shaft's shape and the nock's position relative to the line of travel, which gives two per-frame numbers: how much the shaft is bending (flex) and how far the nock is swinging off direction (yaw). Pooling those numbers per (build, torque, distance) cell yields the early-flight yaw and flex profiles behind the early-flight-characteristics report.

The slow-motion methodology splits across two pages so each stays readable:

• Slow-Motion Capture & Preparation covers how each slow-motion clip is captured and turned into a per-shot dataset of in-flight frames with ground-truth calibration.
• Slow-Motion Measurement & Aggregation covers how each TIFF stack becomes per-frame yaw and flex numbers, how those numbers roll up into per-build trajectories, and what the pipeline still gets wrong.

This slow-motion test is a supplement, not a replacement, for the group-size protocol above. The FoC matrix conclusions in the results articles come from the 70-yard impact data; the slow-motion footage adds a view of what the arrow is doing in the first few feet that the impact photos can't see.

Where To Read Next

• Why FoC Is Hard To Test
• FoC Analysis Overview
• FoC Analysis Appendix
• Slow-Motion Capture & Preparation
• Slow-Motion Measurement & Aggregation