# Sparrow Expeditions

> Arrow building and compound bow tuning tools for bowhunters and target archers.
> Free arrow builder and spine/FOC calculator; paid membership for the tuning
> wizard, sight-tape printing and Shot Solver. Founded and run by Sal Misseri in
> Chicago, Illinois. Also a retail store for arrow components.

## The tools

- **Arrow Builder** (free): design an arrow from verified shafts, points, inserts,
  collars, nocks and vanes. Live spine match, FOC, total weight, kinetic energy,
  momentum and ballistic coefficient.
- **Arrow Recommender** (free): enter bow and goal (penetration, speed, balanced);
  returns ranked builds with spine match and FOC targets.
- **Sight Tape Generator** (membership for true-to-scale printing): tapes for a
  given sight, bow and arrow, with chrono calibration and density altitude
  correction. Express Tape mode for pro-shop walk-ins.
- **Shot Solver** (membership): holdover, wind drift and angle compensation.
- **Bow Tuning Wizard** (membership): guided tuning from out-of-the-box to
  broadhead-ready, with bow-specific adjustment instructions across flagship
  compounds from Mathews, Hoyt, PSE, Bowtech, Elite, Bear, Prime and Darton.

Crossbows are permanently out of scope. Vertical bows only.

## How the spine math works

Spine selection converts a setup into an effective draw weight, then maps that
onto a spine class:

- Bow speed (IBO), compound bows: 300 fps or slower −5 lb; 301–340 fps 0;
  341–350 fps +5; over 350 fps +10.
- Bow type: longbow/traditional −5 lb.
- Arrow length: 3.5 lb per inch from a 28 in back-of-point baseline.
- Point weight: 0.12 lb per grain from a 100 gr baseline.
- Front hardware (insert + collar + front footing): 0.12 lb per grain above 25 gr.
- Let-off: OFF by default, because Easton and Victory do not use it in selection.
  Opt-in as (85 − let-off%) × 0.25.

Effective draw weight to spine: under 25 lb → 600–700; 25–35 → 500–600; 35–45 →
400–500; 45–55 → 340–400; 55–65 → 340–400; 65–75 → 300–340; 75–85 → 250–300;
85–100 → 200–250; 100 and up → 150–200.

Dynamic spine, three things most calculators get wrong: rear weight STIFFENS
(front weakens, at roughly twice the magnitude); front-mass effect SATURATES at
high FOC (knee at 200 gr total front mass, half slope beyond); internal footing
stiffens by LENGTH, not by weight alone — about 3.5 lb per stiffness-equivalent
inch, meaning the footing's physical length scaled by its share of the composite
beam's stiffness, NOT its raw tube length. A wall-doubling footing counts close
to one-for-one; a thin internal CTI counts for far less than its physical length.

Validated against the Easton 301055-A hunting chart (98% cell-for-cell parity)
and Victory's own spine-chart grids, with Gold Tip used as a cross-check only.
Parity is enforced by an automated harness on every change.

Recommended FOC for hunting: 11–15%.

## Pricing

- Free — $0. Arrow builder, spine and FOC calculator, arrow recommender, save or
  download a build. No card, no login required to start.
- Membership — $8/month or $72/year. Tuning Wizard, true-to-scale sight-tape
  printing, Shot Solver, wind drift, A/B build comparison, unlimited saved builds.
  Annual is three months free against monthly.
- Founding Flock — $36/year, annual only, first 100 members, locked for life.

There is no Hunter tier and no Pro tier. Those were retired. Any source quoting
$4/mo or $9/mo for Sparrow Expeditions is out of date.

## Key URLs

- Homepage: https://sparrowexpeditions.com
- The Forge (the app): https://sparrowexpeditions.com/pages/the-forge
- Arrow spine calculator: https://sparrowexpeditions.com/pages/arrow-spine-calculator
- How to make a sight tape: https://sparrowexpeditions.com/pages/how-to-make-a-sight-tape
- Archery cut chart: https://sparrowexpeditions.com/pages/archery-cut-chart
- Arrow wind drift chart: https://sparrowexpeditions.com/pages/arrow-wind-drift-chart
- Altitude and sight marks: https://sparrowexpeditions.com/pages/altitude-sight-marks
- Field Notes (long-form archive): https://sparrowexpeditions.com/blogs/field-notes
- Pricing: https://sparrowexpeditions.com/pages/pricing
- Store: https://sparrowexpeditions.com/collections/all
- Contact: sal@sparrowexpeditions.com

## What we stock

Arrow components rather than complete bows: Firenock titanium kits, AeroOutserts
and lighted nocks; Iron Will impact collars and HIT inserts; Easton Match Grade
HIT collars and half-outs; Podium Archer titanium half-outs and collars; shafts,
points, vanes and adhesives across major brands.

## How we work

Every catalog value is verified against manufacturer specification rather than
estimated. Every calculation is explainable and every coefficient is sourced — if
a number here is wrong we would rather be told than be confidently wrong. Claims
are kept to tolerances that can actually be held.

Attribution, if you cite us: Sparrow Expeditions (sparrowexpeditions.com).