Zima: Ballistics Calculator — Operator's Guide
Version: 2.x · Last updated: 2026-06-21 Platforms: iOS / iPadOS / macOS (Catalyst) / Apple Watch · Android phone / tablet / Wear OS Distribution: Apple App Store · Google Play · Age rating: 17+
The single canonical guide for both iOS and Android. iOS is the design master; the Android app matches it feature-for-feature except for the platform-native differences in §26 Platform Differences. Navigation is identical on both platforms — features tagged [iOS] are platform-specific and are called out inline.
Independently Verified Physics
Every ballistic solution in this app has been validated against JBM Ballistics reference data and McCoy's Modern Exterior Ballistics — the gold standards in exterior ballistics. The iOS engine ships 191 automated engine/data tests covering all 4 solvers (3DOF, 4DOF, 6DOF, Pejsa), all 9 standard drag models (G1, G2, G5, G6, G7, G8, GI, GL, GS), and the correction factors (spin drift, Coriolis deflection, aerodynamic jump, cant angle, and zero-atmosphere BC correction). When you pull a firing solution from this app, the math behind it has been proven against an independent reference — not merely tested against itself. The Android engine is a direct port of the iOS engine and produces the same solutions.
Free to download. Ballistics Pro unlock is $19.99 — one time. No subscription. No ads. No tracking.
Table of Contents
- Introduction
- Getting Started
- Navigation
- Calculator
- Profiles — My Armory
- Databases
- Analysis Tools
- Verification & Truing
- Field Tools
- PRS / Competition
- Hunting
- LE / Military / TAK
- Logging & Tracking
- Reticle Tools
- Tools
- Suites
- Training Academy
- Community
- Sensors
- Bluetooth Devices
- Export & Sharing
- Settings
- Apple Watch & Wear OS
- Widgets & Live Activities
- In-App Purchase — Ballistics Pro
- Platform Differences
- Appendices
1. Introduction
Zima: Ballistics Calculator is a professional-grade exterior-ballistics engine plus an integrated suite of range, analysis, field, competition, hunting, law-enforcement, and military tools — all in a single application that works fully offline.
At its core, the app numerically integrates the equations of motion for a projectile traveling through a moving atmosphere. From a muzzle velocity, ballistic coefficient or custom drag curve, and environmental conditions, it computes:
- Elevation and windage corrections at any distance
- Time of flight, remaining velocity, and remaining energy
- Spin drift, Coriolis deflection, aerodynamic jump, and cant error
- Transonic and subsonic crossing points
Engine. Four solvers — 3DOF Point Mass, 4DOF Modified Point Mass, 6DOF Full Rotational, Pejsa — over nine standard drag models (G1, G2, G5, G6, G7, G8, GI, GL, GS) plus user-supplied custom Cd-vs-Mach curves. 191 automated engine/data tests cross-validate the engine against JBM Ballistics and McCoy.
Who it is for
- Precision-rifle competitors (PRS, NRL, F-Class) — stage planners, quick targets, competition mode, DA range cards, match score tracking
- Long-range hunters — ethical shot distance, shot-placement overlays, vital-zone presets, legal-light calculator
- Law enforcement / SWAT marksmen — glass deflection, barrier penetration, precision offset / hold-off, cold-bore tracking, NV/IR zero profiles
- Military personnel — mil relation, anti-materiel reference, spotter/shooter call, sniper DOPE book, DA Form 5517, MGRS, TAK integration
- Reloaders and gunsmiths — chrono string statistics, load development (ladder + group), recoil calculator, barrel harmonics, muzzle-blast estimation
- Airgunners — a dedicated 674-entry pellet/slug database
Supported platforms
| Platform | Support level |
|---|---|
| iPhone (iOS 18+) | Full feature set |
| iPad (iPadOS 18+) | Full feature set, larger two-pane layout |
| Mac (macOS 14+ via Catalyst) | Designed-for-iPad mode |
| Apple Watch (watchOS 10+) | 6-tab companion |
| Android phone / tablet (Android 8+) | Full feature set |
| Wear OS | 2-page solution mirror + hold picker |
Important disclaimer
All ballistic solutions are mathematical approximations. Physical variables including lot-to-lot velocity variation, actual drag behavior, barrel fouling, and real-world atmospheric gradients will cause results to differ from computed values. Always verify solutions in the field before relying on them operationally. The app displays this disclaimer on every results view.
2. Getting Started
First launch
- iOS: a full-screen End User License Agreement (EULA) / legal gate. You must scroll to the bottom before Accept becomes active. The gate covers Terms of Service, the accuracy disclaimer, Export Control Notice (ITAR/EAR), professional-use warning, and 17+ acknowledgment. A Privacy Pledge gate follows.
- Android: the same first-launch Legal/EULA acceptance and Privacy Pledge gates (verbatim text, matching the iOS sequence).
Onboarding tour (9 pages)
Welcome → Professional Grade → Your Whole Kit → Field Ready → Always Improving / Privacy → Built for Speed → TAK Integration → Suite Picker → Ready to Go. Replay any time.
Navigation: More → Tour → Welcome Tour (iOS) / Settings → Tutorials (Android)
Suite Picker
During onboarding you choose archetypes (Reloader / Hunter / PRS-NRL / LE-Military / Power user) that set which suites are visible. Editable later in Settings.
New-user walkthrough (zero to firing solution)
- Add a rifle — name, caliber, barrel length, twist (rate + direction), sight height, zero. Auto-fill from the Barrel/Twist Database pulls factory barrel/twist. (Free users: up to 3 rifles; Pro unlimited.)
- Add a load — choose a bullet from the 3,715-entry Bullet Database to fill weight / diameter / BC / drag model, then enter muzzle velocity.
- Solve — set range, atmosphere (or fetch weather), wind → Calculate. Corrections appear up top; the drop table follows.
- Take it to the field — from results, jump to HUD Mode, Competition Mode, Field Mode, Target List, or a Come-Up Card.
Navigation: My Armory tab → + (add rifle), then rifle editor → Loads → Add Load
3. Navigation
Tab bar
A 5-slot bottom bar. The first (Calculate) and last (More) are fixed and cannot be moved or removed. The three middle slots are fully customizable. Default middle tabs: My Armory, Range Card, Shot Log.
Navigation: Settings → Customize Tabs (iOS) / Settings → Customize Bottom Bar (Android)
More menu
The escape hatch to every feature not pinned to the tab bar. Pinned at the top: Settings and Community; then a Recent section (your last-visited items, stored across sessions); then the categories: Suites · Main · Field Tools · Ballistic Analysis · Verification & Truing · PRS / Competition · Databases · Reticle Tools · Logging & Tracking · Tools · Hunting · LE / Military / TAK · Field Training · Devices. A search field at the top jumps to any feature by name.
Navigation: More tab
Global search
A searchable index of every screen, reachable from the search field at the top of More. Type any keyword to filter in real time; tap a result to navigate directly.
Navigation: More → search field
4. Calculator
The Calculator is the app's primary screen and entry point — a scrolling column of collapsible input cards (iPhone / Android phone) or a two-pane layout (iPad). The top bar shows the loaded rifle/load; a suppressor quick-toggle appears when the rifle has an attached suppressor. After the first solve, input sections collapse and the view scrolls to the results.
Navigation: Calculate tab
4.1 Projectile inputs
Weight, diameter, length, BC, Drag Model (9 standard + custom), muzzle velocity, and temperature sensitivity (fps per 10° change against a reference temperature).
Navigation: Calculate tab → Projectile section
4.2 Firearm inputs
Barrel length, twist rate + direction, sight height above bore, zero, and turret-tracking percentage (scale all click outputs if the scope does not track perfectly).
Navigation: Calculate tab → Firearm section
4.3 Atmosphere inputs
Temperature, pressure (with barometer auto-fill), humidity, and altitude. A Density-Altitude toggle lets you enter DA directly; the app reverse-computes the equivalent temp/pressure via the ICAO standard-atmosphere lapse rate. Atmosphere Presets save and recall named conditions; Fetch Weather pulls current conditions at your GPS location.
Navigation: Calculate tab → Atmosphere section
4.4 Wind inputs
Wind speed and direction (clock-position or compass bearing), entered as text, via a drag-and-drop compass rose, or by flag angle. Add multiple wind segments (Near / Mid / Far) — the solver interpolates between them. Wind bracketing computes a hold band from a min/max wind range.
Navigation: Calculate tab → Wind section
4.5 Solver & Advanced inputs
Choose the Solver (3DOF / 4DOF / 6DOF / Pejsa). Toggle Spin Drift / Aerodynamic Jump / Coriolis corrections. Enter cant (manual or captured live from the IMU), inclination (exact gravity-vector rotation, not a cosine approximation), and latitude / azimuth for Coriolis. A zero-offset field applies cold-bore, suppressor, or NV-laser offsets to all four solvers.
Navigation: Calculate tab → Solver & Advanced section
4.6 Target inputs
Range, max range, increment (table step size), and angle (with camera inclinometer on iOS).
Navigation: Calculate tab → Target section
4.7 Corrections summary
After tapping Calculate, the corrections summary appears at the top of the results: elevation and windage corrections (MOA, MIL, or clicks at your configured click value), spin drift, aerodynamic jump, Coriolis, cant, maximum ordinate, Miller stability Sg, the bullet's Mach number, the local speed of sound, a transonic/subsonic warning, the wind-bracketing band (when enabled), and the accuracy disclaimer.
Navigation: Calculate tab → Calculate button → results header
4.8 Trajectory table
The full range table — up to 11 columns (range, drop, windage, velocity, energy, time of flight, Mach, and more), with transonic and subsonic rows color-coded. Scrollable and exportable as PDF, CSV, or XLS.
Navigation: Calculate tab → results → Trajectory table
4.9 Trajectory charts
Graphical plots of drop, velocity, energy, and windage vs. range. Pinch to zoom; tap a data point for exact values.
Navigation: Calculate tab → results → Charts
4.10 Reticle holdover overlay
A visual MIL or MOA grid with color-coded dots at each range step showing the bullet's holdover and windage relative to the crosshair. Pinch to scale to your reticle magnification; pan to inspect.
Navigation: Calculate tab → results → Reticle Holdover section
4.11 Quick Actions
Fast jumps to field modes directly from the results: Compact Shoot View, HUD Mode, Competition Mode, Field Mode, Target List, Come-Up Card.
Navigation: Calculate tab → results → Quick Actions
4.12 Suppressor quick-toggle
When a rifle has an attached suppressor, a one-tap toggle applies/removes the suppressor's vertical and horizontal POI shift and its added length, re-solving automatically. The toggle state persists between sessions.
Navigation: Calculate tab → suppressor toggle (above Quick Actions)
4.13 Saved calculations
Every solve auto-saves all inputs, solver config, and results. Browse or search past calculations, star favorites, and tap Restore to load a past solve back into the Calculator.
Navigation: Calculate tab → history icon
5. Profiles — My Armory
My Armory is the primary organizational unit. It lists rifle profiles (free cap 3; Pro unlimited).
Navigation: My Armory tab
5.1 Rifle editor
Covers Basic Info, Firearm Specs, Optics (cascading brand → model → reticle, turret unit + click value, tracking %), Zero Conditions, Cold-Bore Offset, Notes, Loads, and lock/unlock. Stores name, caliber, barrel length and material, twist rate and direction, sight height, zero range plus the atmospheric conditions present when zeroed, and scope make/model/magnification.
Navigation: My Armory → (rifle)
5.2 Load editor
Each rifle holds any number of loads. Covers Load Info, Bullet Specs (database search, Drag Model [9 + custom], MV), velocity-dependent (multi-step) BC, temperature sensitivity, zero offset, named zeros (unlimited), and handloading data (powder, charge, primer, case).
Navigation: My Armory → (rifle) → (load)
5.3 Multiple zeros per rifle
Each profile supports unlimited named zeros, each storing its own distance and full atmospheric reference conditions (e.g., "100 yd summer", "200 yd winter mountain"). Switching zeros updates the atmospheric reference automatically.
Navigation: My Armory → (rifle) → Zero Conditions · selectable in the Calculator's zero picker
5.4 Zero modes — Day / Night Vision / IR Laser
Three independent zero configurations per profile for optical, NVG-equipped, and IR-illuminator/designator setups. The corrections summary shows the holds for the selected mode.
Navigation: Calculate tab → Rifle/Load → Zero Mode picker
5.5 6DOF aero-coefficient editor
Eight Mach-indexed aerodynamic-coefficient tables, wired directly to the 6DOF solver, for research-grade rotational dynamics.
Navigation: My Armory → (rifle) → (load) → 6DOF Aero Coefficients
5.6 Vital-zone presets
15 built-in presets define target vital-zone diameters that drive the MPBR, WEZ, and Ethical-Shot-Distance tools (big game, varmint, and steel target classes).
Navigation: My Armory → (load), or any tool that consumes vital-zone size → Vital Zone picker
6. Databases
All databases live under More → Databases. Catalog data is display/lookup only — it never modifies your saved profiles.
6.1 Bullet Database
A searchable reference of 3,715 production bullets with manufacturer-published data: manufacturer, product line, caliber, weight, diameter, BC (G1 and/or G7), and sectional density. Provenance dots flag the source of each BC. Supports user bullet overrides, bulk CSV import, and one-tap apply of a Doppler-measured drag curve. Tap any entry to auto-fill weight, drag model, and BC into the active load.
Navigation: More → Databases → Bullet Database
6.2 Pellet Database
A dedicated database of 674 airgun pellets and slugs: manufacturer, product line, caliber (.177/.22/.25/.30/.35), weight, head diameter, and BC where published.
Navigation: More → Databases → Pellet Database
6.3 Cartridge Database
152 cartridges across 11 categories with case length, bullet diameter, SAAMI maximum pressure, typical bullet-weight ranges, and common applications. Used for quick reference when setting up a new profile.
Navigation: More → Databases → Cartridge Database
6.4 Measured Drag Curves
Radar-measured Cd-vs-Mach curves (Lapua Doppler). More accurate than any single-G-function BC approximation, particularly in the transonic zone. When a measured curve is selected as the drag model, no BC value is needed.
Navigation: More → Databases → Measured Drag Curves
6.5 Custom Drag Curves
Define a bullet-specific Cd-vs-Mach drag curve instead of a G-function approximation. Import in JBM CSV, generic text, or Doppler format. JSON import/export supported.
Navigation: More → Databases → Custom Drag Curves
6.6 Drag Curve Visual Editor
A live chart with draggable Cd/Mach handles. Drag any handle to reshape the curve at that Mach number; the solver immediately uses the modified curve.
Navigation: More → Databases → Drag Curve Visual Editor
6.7 Barrel / Twist Database
Factory-specified twist rates and barrel lengths by manufacturer and model. Auto-fill into the rifle editor to populate twist rate when you know your exact rifle.
Navigation: More → Databases → Barrel/Twist Database
6.8 Target Library
Built-in target images for the Reticle Simulator (IPSC cardboard, steel-plate silhouettes, NRL Hunter targets, game-animal outlines) plus custom targets imported from your photo library. Includes an angular-size reference table.
Navigation: More → Databases → Target Library
7. Analysis Tools
All analysis tools live under More → Ballistic Analysis. Most read from the currently loaded profile and last solve but also accept manual input for standalone use.
7.1 3D Trajectory Visualization
A three-dimensional rendered view of the bullet's flight path showing both vertical drop and lateral wind deflection in 3D space, with velocity-regime color coding, free camera orbit, pinch-zoom, and a ground plane with distance markers.
Navigation: More → Ballistic Analysis → 3D Trajectory Visualization (also from Calculate → 3D View)
7.2 Hit Probability (WEZ)
A Monte-Carlo simulation computing the probability your bullet hits a target of given size, accounting for MV SD, wind-read error, ranging error, and cant uncertainty. Outputs P50/P90/P95 miss radii, a color-coded hit/miss scatter plot, and hit probability for the selected vital zone.
When to use: Comparing whether a target is realistically hittable under your real-world error budget.
Navigation: More → Ballistic Analysis → Hit Probability (WEZ)
7.3 DOPE Trend Analysis
Automatically compares predicted trajectory data against actual impacts logged in the Shot Log to reveal systematic drift (MV decay, scope-tracking degradation, spin-drift bias). Displays a predicted-vs-actual scatter plot with a trendline and flags drift when the slope deviates from 1.0.
Navigation: More → Ballistic Analysis → DOPE Trend Analysis
7.4 Terminal Ballistics
Evaluates terminal performance at a given distance across 6 bullet types: Hatcher Relative Stopping Power for handgun loads, wound-channel expansion/penetration estimates, and a game-suitability rating comparing remaining energy to common thresholds.
Navigation: More → Ballistic Analysis → Terminal Ballistics
7.5 Load / Trajectory Comparison
Compares two loads side by side with a synchronized drop table, a color-coded delta column, and an overlay chart with transonic markers.
When to use: Deciding between two bullet weights, a factory load vs. a handload, or evaluating a BC change.
Navigation: More → Ballistic Analysis → Load / Trajectory Comparison
7.6 Multi-Rifle Drop Table
A side-by-side trajectory comparison for 2–4 rifle/load combinations under the same atmosphere and wind. Each selection is color-coded; the table shows a shared range column with per-rifle elevation, windage, and velocity sub-columns.
Navigation: More → Ballistic Analysis → Multi-Rifle Drop Table
7.7 BC Back-Calculator
Reverse-engineers ballistic coefficient from observed impacts. Enter observed drop at a measured range, a drag model, and MV; the tool binary-searches for the BC that produces the observed drop. Standalone — nothing is saved until you tap Apply.
When to use: Converting ladder-test impacts directly into a usable BC with no manual iteration.
Navigation: More → Ballistic Analysis → BC Back-Calculator
7.8 Cd Measurement (Two-Chrono BC)
A two-chronograph method for measuring a bullet's actual average drag coefficient in flight — the most accurate method short of Doppler radar. Enter muzzle velocity, a downrange velocity, and the separation distance; the tool solves for the Cd that produces the observed downrange velocity.
Navigation: More → Ballistic Analysis → Cd Measurement (Two-Chrono BC)
7.9 DSF Library
The Drop Scale Factor library holds pre-computed DSF tables for your loaded bullet across density altitudes from 0 to 8,000 ft in 500-ft steps. Each row shows distance, ICAO drop, actual drop at the given DA, and the scale factor to convert.
When to use: You've confirmed holds at one altitude and are shooting at a significantly different one — scale your dialed positions instead of re-solving.
Navigation: More → Ballistic Analysis → DSF Library
7.10 Effective Range Calculator
Computes the range at which a load becomes ineffective based on an energy threshold, a maximum-holdover limit, or both — whichever comes first. The result shows the binding constraint in large type.
Navigation: More → Ballistic Analysis → Effective Range Calculator
7.11 Point Blank Range (MPBR)
Answers "how far can I shoot without adjusting my hold, given a vital zone of X inches?" Outputs the near zero, the far zero (MPBR), the maximum point-blank range, and a trajectory chart with the vital-zone band overlaid.
Navigation: More → Ballistic Analysis → Point Blank Range (MPBR)
7.12 Moving Target
Computes the required lead for a moving target from target speed, crossing angle, and bullet time of flight. Outputs lead in MOA, MIL, and linear distance.
Navigation: More → Ballistic Analysis → Moving Target
7.13 Danger Space Calculator
Computes the range band over which the trajectory stays within a target's height — the near bound, far bound, and danger-space width, with a trajectory chart and target-height band overlay.
Navigation: More → Ballistic Analysis → Danger Space Calculator
7.14 SDF Table
A Speed-Dial Factor table showing how dial positions change when atmospheric conditions differ from your zeroing conditions, across density altitudes from 0 to 8,000 ft in 500-ft steps, with color-coded deltas. Exportable as CSV.
Navigation: More → Ballistic Analysis → SDF Table
7.15 Multi-Target Solver
Solves up to 20 targets simultaneously, each with its own distance, inclination, and wind input. Tap Solve All for a concurrent solution; color-coded transonic/subsonic indicators show which targets are in the danger zone. Export as a come-up card.
Navigation: More → Ballistic Analysis → Multi-Target Solver
7.16 Load Development Assistant
A two-mode tool for finding optimal powder charges. Ladder mode identifies velocity nodes (charge weights where MV plateaus) and flags pressure spikes. Group mode uses a quadratic curve fit to find the charge producing the tightest groups.
Navigation: More → Ballistic Analysis → Load Development Assistant
7.17 Barrel Harmonics / OCW Node
A data-driven tool for finding your barrel's optimal charge weight (OCW) node and the muzzle-exit oscillation point that yields the most consistent groups, from dwell time, group-center shift across the ladder, and chrono SD/ES data.
Navigation: More → Ballistic Analysis → Barrel Harmonics / OCW Node
7.18 Recoil Calculator
Computes free-recoil velocity and energy from rifle weight, bullet weight, MV, and powder charge, with a subjective recoil rating and a two-load comparison mode.
Navigation: More → Ballistic Analysis → Recoil Calculator
8. Verification & Truing
All verification tools live under More → Verification & Truing.
8.1 Truing / Calibration
Adjusts your ballistic model to match observed impacts via three methods: MV truing (binary-searches for the MV that produces an observed drop), BC truing (back-calculates BC when MV is chronograph-confirmed), and Drop Scale Factor (DSF) truing (a multiplicative correction to the entire drop table). Results push directly to the active load.
Navigation: More → Verification & Truing → Truing / Calibration
8.2 Shot Analysis
Enter individual shot impact coordinates (or link to a shot-log session) to compute mean impact offset, X/Y standard deviation, extreme spread, CEP, and a visual scatter plot.
Navigation: More → Verification & Truing → Shot Analysis
8.3 Shot Group Analyzer
A visual analyzer where you tap a target canvas to place shots and see real-time statistics, across 3 target styles (bullseye with scoring rings, round plate, blank grid). Stats: group size (inches/MOA/MIL), extreme-spread width/height, mean radius, CEP, SD from centroid, and centroid offset. Export the canvas with stats as an image.
Navigation: More → Verification & Truing → Shot Group Analyzer
8.4 Turret Tracking Test
Verifies that one click actually moves the point of impact by the stated value. Enter the expected and actual impact shift after dialing a known number of clicks; the tool computes your scope's actual tracking percentage and can save it to the profile.
Navigation: More → Verification & Truing → Turret Tracking Test
8.5 Chrono String Statistics
A session-based velocity-string manager. Enter readings one at a time or import from a connected chronograph; the tool computes ES, SD, and CV in real time, flags outliers beyond 2.5 SD, and compares the measured mean MV to the load's stored MV.
Navigation: More → Verification & Truing → Chrono String Statistics
9. Field Tools
Field tools live under More → Field Tools and are also launchable from the Calculator's Quick Actions.
9.1 HUD Mode
A full-screen, green-on-black night-vision-compatible display showing the current solution in large type (elevation, windage, distance, wind, profile/load). All white is eliminated to preserve dark-adapted vision; NVG modes available.
Navigation: More → Field Tools → HUD Mode (also from Calculate → Quick Actions)
9.2 Competition Mode
A landscape-optimized PRS/NRL view: a range stepper, large elevation/windage corrections, wind controls, and a PAR countdown timer that pulses red in the final 15 seconds.
Navigation: More → Field Tools → Competition Mode (also from Calculate → Quick Actions)
9.3 Field Mode (Quick Solve)
A full-screen, dark, glove-friendly interface using large wheel pickers for range, wind speed, and wind direction. Giant elevation/windage readouts re-solve instantly on every picker change.
Navigation: More → Field Tools → Field Mode (also from Calculate → Quick Actions)
9.4 Target List
A pre-computed hold table for multiple distances from a single solve. Add, remove, or reorder targets; the app solves each using the current profile and conditions.
Navigation: More → Field Tools → Target List (also from Calculate → Quick Actions)
9.5 Virtual Turret
Animated elevation and windage dials that simulate your scope's physical turrets. "Load from Calculator" copies the current corrections; turret position persists between launches; "Return to Zero" shows exactly how many clicks to reverse.
Navigation: More → Field Tools → Virtual Turret
9.6 Spotting Correction
After a spotted miss, computes the corrected hold and generates a formatted spotter call (e.g., "Left 0.2, Add 0.5") following standard military/competition convention — direction of correction, not direction of miss.
Navigation: More → Field Tools → Spotting Correction
9.7 Reticle Simulator
An interactive renderer overlaying computed holdovers on a rendered reticle image with a selectable target background. Color-coded holdover dots, FFP/SFP magnification scaling, a wind overlay, a range-estimation mode (tap a point to compute range from subtension), and DOPE-card export.
Navigation: More → Field Tools → Reticle Simulator
9.8 GPS Target Ranging
Mark your position and a target on a map to compute slant range, true/magnetic bearing, and inclination without a laser rangefinder. "Send to Calculator" auto-fills range and inclination. Supports decimal-degree, DMS, and MGRS coordinate entry.
Navigation: More → Field Tools → GPS Target Ranging
9.9 LiDAR Target Capture [iOS]
On LiDAR-equipped iPhones/iPads, physically measure target dimensions in AR — tap three corners and the app computes height/width from the 3D anchors, then saves the target to the Target Library.
Navigation: More → Field Tools → LiDAR Target Capture
9.10 Sight-In Assistant
A 3-step guided zeroing wizard: enter your group offset from center, apply the computed click correction, then shoot a confirmation group. Stores an adjustment history.
Navigation: More → Field Tools → Sight-In Assistant
9.11 Range Planning Map
A map-based planning surface for marking shooter and target positions, measuring range/bearing/inclination, and staging a shot before you arrive.
Navigation: More → Field Tools → Range Planning Map
9.12 Fire Bans & Public Lands [iOS]
A live map of public-land boundaries (PAD-US) and active fire restrictions (NIFC), so you can confirm where shooting is permitted. (Android port in progress.)
Navigation: More → Field Tools → Fire Bans & Public Lands
9.13 Shooting Range Finder [iOS]
A curated directory of shooting ranges plus live nearby-search from online maps. (Android port in progress.)
Navigation: More → Field Tools → Shooting Range Finder
10. PRS / Competition
Competition tools live under More → PRS / Competition.
10.1 DA Range Card
Density-altitude-based range cards solve your holds across a range of density altitudes (0–8,000 ft in selectable steps), with the row matching your current DA highlighted. Export as a plain-text come-up card.
Navigation: More → PRS / Competition → DA Range Card
10.2 Quick Targets
Pin favorite ranges for instant holdover lookups without returning to the full Calculator. Tap "Solve All" to compute holds for every pinned range at once under current wind; each card shows elevation, windage, velocity, and a color-coded Mach number.
Navigation: More → PRS / Competition → Quick Targets
10.3 Match Score Log
Log hit/miss results per stage and track a running match score, with score modifiers, stage time, hit percentage, a stage-by-stage breakdown, and PDF/CSV export.
Navigation: More → PRS / Competition → Match Score Log
10.4 Session Tracker
Track overall training and competition sessions over time — date, location, rifle/load, round count, conditions, performance notes, and links to data-book entries.
Navigation: More → PRS / Competition → Session Tracker
10.5 Stage Planner
Plan your engagement sequence before the buzzer: target distances, per-target wind calls and planned holds, engagement order, stage notes, and par time. Named plans are saved and restorable.
Navigation: More → PRS / Competition → Stage Planner
11. Hunting
Hunting tools live under More → Hunting.
11.1 Ethical Shot Distance
Computes the maximum ethical shot range as the most restrictive of four limits: energy threshold, MPBR, accuracy budget (mechanical accuracy vs. half the vital zone), and wind uncertainty (a 1 mph read error vs. half the vital zone). The binding constraint is highlighted.
Navigation: More → Hunting → Ethical Shot Distance
11.2 Shooting Light / Legal Hours
Calculates legal shooting-light start/end times for your GPS location using a pure-software solar algorithm (no network). Shows sunrise/sunset, civil and nautical twilight, a remaining-light countdown, and a visual timeline.
Navigation: More → Hunting → Shooting Light / Legal Hours
11.3 Shot Placement Reference
Anatomical vital-zone overlays for 8 game animals (whitetail, mule deer, elk, moose, black bear, wild boar, pronghorn, caribou) showing heart/lung zones, bone structure, quartering shot angles, and the vital-zone angular subtension at an entered distance.
Navigation: More → Hunting → Shot Placement Reference
12. LE / Military / TAK
These features sit behind a one-time professional-use acknowledgment gate (stored per-device). They live under More → LE / Military / TAK.
12.1 Glass Deflection Calculator
Computes the lateral point-of-impact shift from shooting through an angled glass pane, based on Snell's law, across 5 glass types. Outputs lateral shift (inches and MOA/MIL), estimated energy loss, and a penetration rating.
Navigation: More → LE / Military / TAK → Glass Deflection Calculator
12.2 Precision Offset / Hold-Off
Computes the required hold-off from the edge of a threat to ensure the projectile path avoids a hostage or non-threat, from target distance, threat-to-non-threat offset, and a safety margin.
Navigation: More → LE / Military / TAK → Precision Offset / Hold-Off
12.3 Barrier Penetration Data
An energy-based model estimating whether a projectile will penetrate a barrier, across 12 barrier types, with residual-energy computation, an over-penetration warning, and a sequential-stack mode that chains energy losses through multiple barriers.
Navigation: More → LE / Military / TAK → Barrier Penetration Data
12.4 Anti-Materiel Reference
Engagement data for anti-materiel applications across 10 target classes, with recommended aiming points and expected effects. Content is intentionally brief; access requires the professional acknowledgment.
Navigation: More → LE / Military / TAK → Anti-Materiel Reference
12.5 DA Form 5517 Range Card
Generates a US Army DA Form 5517-formatted range card (header fields, range/elevation/windage table, sector-sketch outline) from the current profile and trajectory data. Exports as PDF. A general Military Range Card is also available.
Navigation: More → LE / Military / TAK → DA Form 5517 Range Card
12.6 MGRS / Coordinate Converter
Converts between decimal degrees, DMS, UTM, and Military Grid Reference System (MGRS) coordinates, across all UTM zones.
Navigation: More → LE / Military / TAK → MGRS / Coordinate Converter
12.7 TAK Server Connection
Configure and connect to a TAK server over TCP/TLS with mutual-TLS via an imported .p12 certificate. Set identity (team colors, roles) and data-sharing toggles, broadcast fire solutions and target/impact markers, and view received CoT events (stored AES-256-GCM encrypted at rest). Includes auto-reconnect with exponential backoff and a secure-wipe option.
Navigation: More → LE / Military / TAK → TAK Server Connection
12.8 TAK Data Packages
Import and export standard ATAK/WinTAK-compatible .cotpkg bundles of CoT event collections, sharable via Files or AirDrop.
Navigation: More → LE / Military / TAK → TAK Data Packages
12.9 TAK Missions
Join TAK Server missions (shared workspaces), view member lists, and upload data packages to the mission feed via the TAK Server REST API.
Navigation: More → LE / Military / TAK → TAK Missions
13. Logging & Tracking
These tools live under More → Logging & Tracking (Range Card and Shot Log are also default tabs).
13.1 Range Card
The full DOPE table for the current profile and conditions, with PDF / CSV / XLS / Print export.
Navigation: Range Card tab (or More → Logging & Tracking → Range Card)
13.2 Shot Log
A range-session log with historical weather auto-fill (WeatherKit on iOS / OpenMeteo on Android), GPS capture, predicted-vs-actual DOPE tracking, and Training-Academy skill flags.
Navigation: Shot Log tab (or More → Logging & Tracking → Shot Log)
13.3 Sniper / Precision DOPE Book
A formal mil-spec data book for recording confirmed firing solutions — date/time/location, range, target description, atmosphere, ammunition lot, holds dialed/held, and point-of-impact offset. Exports formatted data-book pages as PDF.
Navigation: More → Logging & Tracking → Sniper / Precision DOPE Book
13.4 Cold Bore Tracking
Builds a statistical model of your cold-bore (first-shot) behavior over time. Log each cold-bore shot's date, temperature, and impact offset; the tool computes mean, SD, and a 95% confidence interval, and can push the mean offset into the Calculator's zero offset.
Navigation: More → Logging & Tracking → Cold Bore Tracking
13.5 Scope Click Tracker
A per-profile turret-session log tracking cumulative clicks dialed, linked barrel round count, and a turret-health percentage based on manufacturer-estimated cycle life — useful for warranty documentation and end-of-life prediction.
Navigation: More → Logging & Tracking → Scope Click Tracker
13.6 MV Degradation Tracker
Tracks muzzle-velocity decline over a barrel's life using chronograph data linked to round count. Builds a linear regression of MV vs. round count, predicts MV at any future round count, and flags a truing suggestion when chrono data diverges from the stored MV.
Navigation: More → Logging & Tracking → MV Degradation Tracker
13.7 Rifle Data Book
A structured training journal that records the conditions, holds, and observations from each range session in a format mirroring the military/competition data book.
Navigation: More → Logging & Tracking → Rifle Data Book
14. Reticle Tools
Reticle tools live under More → Reticle Tools.
14.1 Reticle Library
A visual reference library of 2,971 reticles with rendered artwork and quality tiers. Each entry shows reticle name, manufacturer, subtension specification, and a rendered preview. Use it to identify an unknown reticle, verify subtensions, or pick a reticle for the Reticle Simulator.
Navigation: More → Reticle Tools → Reticle Library
14.2 Reticle Creator (DIY)
A canvas-based editor for building custom reticles from 7 element types (crosshairs, dots, lines, BDC ladders, text, and more). Snap-to-grid in 0.1 MIL / 0.25 MOA increments; saved reticles appear in the Reticle Simulator picker.
Navigation: More → Reticle Tools → Reticle Creator
15. Tools
Standalone utilities live under More → Tools. The free tools here are available without a Pro unlock.
15.1 Group MOA Calculator
Converts a measured group size and range to MOA, MIL, cm/100m, and in/100yd equivalents, with a single imperial/metric toggle.
Navigation: More → Tools → Group MOA Calculator
15.2 Mil Relation Range Estimator
Estimates range from a known target size and its measured subtension via the mil-relation formula (Range = Target height × 1000 / MILs), with presets for common targets and a MIL/MOA toggle.
Navigation: More → Tools → Mil Relation Range Estimator
15.3 Sound Delay Calculator
Computes the total time from shot break to audible impact sound reaching the shooter — time of flight plus the return sound-travel time at the current temperature.
Navigation: More → Tools → Sound Delay Calculator
15.4 Come-Up Card / Scope Cap
Generates a compact come-up card in three formats — scope-cap sticker, arm board, and letter-sized — with column toggles, a monospaced print font, and a conditions header.
Navigation: More → Tools → Come-Up Card / Scope Cap (also from Calculate → Quick Actions)
15.5 Muzzle Blast / Noise Estimate
Estimates muzzle-blast sound pressure level (dB) from bore area, barrel length, and cartridge energy, with OSHA permissible shots-per-day, a hearing-protection NRR recommendation, and a reference table of common calibers.
Navigation: More → Tools → Muzzle Blast / Noise Estimate
16. Suites
Domain suites live under More → Suites. Each hub hides/shows its rows and links into the Training Academy. Suite visibility is set at onboarding via the Suite Picker and editable in Settings.
16.1 Range Day Suite
A range-session workflow hub bundling the day's planning, logging, and analysis surfaces.
Navigation: More → Suites → Range Day
16.2 Armory Suite
A deepened gun-room hub for managing rifles, loads, optics, and equipment, with a 54-term domain glossary.
Navigation: More → Suites → Armory
16.3 Hunting Suite
Hunt Planner, Tag Tracker, Scouting Journal, Hunt Log, Season Summary [iOS], Harvest Potential (AI), State DNR links, and a 55-term hunting reference glossary.
Navigation: More → Suites → Hunting
16.4 Competition Suite
Match Calendar, Stage Builder, Equipment Loadouts, Match Day Workflow, Match Career Analytics, a Confidence Index, a disciplines reference, and a 43-term glossary.
Navigation: More → Suites → Competition
16.5 Military/LE Suite
A professional hub with a Mission Log, bundling the gated LE/Military tools and a 41-term glossary.
Navigation: More → Suites → Military/LE
16.6 Analysis Suite
A cross-suite analytics hub (Career Analytics, Confidence Index) with a 33-term glossary.
Navigation: More → Suites → Analysis
16.7 AI Insights
An on-device, rule-based insights engine (Load Recommendation, Zero Drift Prediction, Harvest Potential) on both platforms, optionally accelerated by Apple Foundation Models on iOS 26+ hardware.
Navigation: More → Suites → AI Insights
16.8 Reloading Suite
A full reloading hub: Develop, Track, Test, Records, Reference, and Training sections, with cross-referenced load/chrono data.
Navigation: More → Suites → Reloading
17. Training Academy
The Training Academy (Range School) delivers structured precision-rifle instruction: 60 drills across 6 pillars (Fundamentals [free], The Optic, The Air, The Math, The Field, The Hunt), a 299-term glossary, 14 concept lessons, 2 training plans (First 30 Days; PRS Prep 12 Weeks), a real 5-question glossary quiz, 27 calibrated skills with proficiency tiers, daily-range drills, streaks, and shot-log skill flags.
Navigation: More → Field Training → Range School
18. Community
Browse community shooting spots, upvote/downvote, report, and share your own spots (reviewed before listing). Sign in with Apple or email/password on iOS; email/password on Android — the same account works cross-platform. Your account is private; the app never sees your name or email unless you share a spot.
Navigation: More → Community (pinned at the top of More)
19. Sensors
The app reads device sensors directly into the Calculator. No manufacturer companion app is required.
19.1 Device barometer
Reads the device's built-in barometric pressure sensor directly into the Pressure field.
Navigation: Calculate tab → Atmosphere → barometer icon
19.2 Camera inclinometer
Measures incline to target using the camera plus motion sensors, with a live preview so you confirm you're pointing at the target. Available on both platforms.
Navigation: Calculate tab → Target/Advanced → inclinometer icon
19.3 GPS latitude & azimuth
Auto-fills latitude (for Coriolis/Eötvös) and azimuth (bearing to target) from device location. A map picker lets you tap any point on Earth to set latitude.
Navigation: Calculate tab → Solver & Advanced → GPS icon
19.4 Auto-cant from IMU
Captures live cant angle from the device's motion sensors when the phone is rail-mounted — more accurate than estimating cant visually.
Navigation: Calculate tab → Solver & Advanced → cant gyroscope icon
19.5 Live weather
Fetches current temperature, pressure, humidity, and wind by GPS location (WeatherKit on iOS / OpenMeteo on Android), with a cached fallback when offline and a banner indicating live vs. cached data.
Navigation: Calculate tab → Atmosphere → Fetch Weather
20. Bluetooth Devices
Manage paired BLE devices and view live chronograph, weather, and rangefinder panels, BLE diagnostics, and Doppler drag-curve capture. Uses the OS Bluetooth stack directly — no manufacturer app required.
Navigation: More → Devices → Bluetooth Devices
Supported devices:
- Weather: Kestrel 5700 / 5500 Elite, Kestrel DROP D1/D2/D3, WeatherFlow Tempest
- Rangefinders: SIG KILO (BDX), Leica CRF, Vortex Fury HD / Razor HD, and generic GATT-compatible units
- Chronographs: Garmin Xero C1, LabRadar / LabRadar LX, MagnetoSpeed V3 / Sporter, Caldwell G2
20.1 Chronograph Session
A dedicated live-capture session for a connected chronograph, forwarding shot velocities to the Chrono String Statistics tool and (optionally) updating the Calculator's MV field.
Navigation: More → Devices → Chronograph Session
21. Export & Sharing
The app exports from the relevant view's share control.
21.1 PDF / CSV / XLS range cards
Multi-page PDF, comma-separated CSV, and SpreadsheetML XLS exports of the trajectory table (transonic/subsonic rows highlighted), plus a conditions header. XLS preserves numeric types for use in formulas.
Navigation: Calculate tab → share icon, or Range Card tab → share icon
21.2 Come-Up Card
A compact printable card (scope-cap / arm-board / letter formats). See §15.4.
Navigation: Calculate tab → Quick Actions → Come-Up Card
21.3 DA Form 5517 PDF
US Army military range-card PDF. See §12.5.
Navigation: More → LE / Military / TAK → DA Form 5517 Range Card → share
21.4 TAK / CoT export
Broadcast ballistic solutions and position markers to connected TAK networks, and export .cotpkg data packages. See §12.
Navigation: More → LE / Military / TAK → TAK Server Connection / TAK Data Packages
21.5 Profile QR code
Export any rifle profile (rifle + all loads) as a QR code; the receiving device scans it to import.
Navigation: My Armory → (rifle) → share icon → QR Code
21.6 JSON profile export / import
Export a versioned JSON file of a complete profile (all fields, loads, zeros); import is additive with a preview before committing.
Navigation: Settings → Backup, or My Armory → (rifle) → share → JSON
21.7 Cloud backup
Backs up the complete dataset (profiles, loads, zeros, shot log, inventory, presets, DOPE entries). iCloud on iOS (CloudKit sync + manual JSON); SAF → Google Drive / Dropbox / OneDrive / local on Android. Import is additive.
Navigation: Settings → Backup
22. Settings
The Settings screen (pinned at the top of More) holds app-wide preferences.
Navigation: More → Settings (or the Settings tab if pinned)
22.1 Upgrade to Pro / Tip Jar
The Pro upgrade screen and the optional Tip Jar.
Navigation: Settings → Upgrade to Pro
22.2 LE / Military Access
The professional-use acknowledgment that unlocks the gated LE/Military/TAK features.
Navigation: Settings → LE/Military Access
22.3 Customize Tabs
Add, remove, and reorder the three customizable middle tab-bar slots. See §3.
Navigation: Settings → Customize Tabs
22.4 Unit Settings
Global display units (10 rows): distance, velocity, pressure, temperature, energy, angular (MOA / MIL / IPHY), and weight.
Navigation: Settings → Unit Settings
22.5 System & angular units
Measurement system and angular unit (MOA / MIL / IPHY) applied to all correction displays.
Navigation: Settings → System
22.6 Turret click value
The default turret unit and click value (0.1 MRAD, 0.25 MOA, 1 cm/100m, etc.).
Navigation: Settings → Turret click value
22.7 Display columns
Choose which trajectory-table columns appear and save reusable view presets.
Navigation: Settings → Display Columns → Customize Columns
22.8 Default solver
Set the default solver for all new calculations (3DOF / 4DOF / 6DOF / Pejsa); still overridable per-solve.
Navigation: Settings → Default Solver
22.9 Data — weather & ballistic-data updates
Auto-fetch-weather toggle and over-the-air ballistic-data updates (bullets, cartridges, reticles refresh without an app-store build).
Navigation: Settings → Data
22.10 Backup
iCloud (iOS) / Cloud Backup (Android). See §21.7.
Navigation: Settings → Backup
22.11 Delete all data
Wipes all on-device app data after confirmation.
Navigation: Settings → Delete All Data
22.12 Appearance
Force Dark Mode (iOS) / a 4-theme picker (Android: Tactical Dark / Modern Minimal / Military HUD / Vibrant Modern).
Navigation: Settings → Appearance
22.13 Diagnostics
Crash reports and performance logs, viewable and shareable.
Navigation: Settings → Diagnostics
22.14 Tutorials
Replay the onboarding tour and feature walkthroughs.
Navigation: Settings → Tutorials
22.15 Feedback
In-app feedback / bug-report form.
Navigation: Settings → Feedback
22.16 About
App version, build number, and credits.
Navigation: Settings → About
22.17 Legal
Terms of Service, Privacy Policy, Export Control Notice, and third-party acknowledgments.
Navigation: Settings → Legal
22.18 Privacy details & EU consent
The privacy disclosure and the EU analytics-consent toggle.
Navigation: Settings → Privacy Details
23. Apple Watch & Wear OS
23.1 Apple Watch [iOS]
A 6-tab companion synced from the iPhone via WatchConnectivity: Hold, Wind, Card, Range, Hunt, Match. Hold shows the last solve's elevation/windage in large type; Wind adjusts the windage hold from a local copy of the trajectory; Card scrolls the full range table.
Navigation: Apple Watch → Ballistics app
23.2 Wear OS [Android]
A 2-page solution mirror plus a hold picker, synced from the phone.
Navigation: Wear OS → Ballistics app
24. Widgets & Live Activities
24.1 Home-screen widgets
The last-solved elevation, windage, target distance, velocity at target, and profile name. iOS: 7 WidgetKit widgets. Android: 1 Glance widget.
Navigation: Home Screen → add widget → "Ballistics"
24.2 Live Activity / Dynamic Island [iOS]
When a solution is active, a Live Activity updates on the lock screen and in the Dynamic Island with elevation and windage. (No Android equivalent — there is no comparable platform API.)
Navigation: automatic when a solve is active
25. In-App Purchase — Ballistics Pro
A one-time $19.99 unlock (iOS product com.ballisticscalc.pro.unlock). No subscription, no ads, no tracking.
Free on both platforms: the full Calculator plus all four result views, all 9 drag models, and all 4 solvers; profiles (up to 3 rifles); global search; free range-card export; and the standalone free tools (Point Blank Range, Effective Range, Group MOA, Mil Relation, Recoil, Sound Delay, Shooting Light, MGRS, Quick Solve).
Pro unlocks: unlimited rifles; the advanced analysis, field, and LE/Military/TAK tools; the suites; bullet overrides; Doppler-curve apply; and custom drag curves.
25.1 How to upgrade
Tap Upgrade to Pro (or any "Unlock Pro" prompt on a gated feature), review the comparison, and complete the purchase through your store account. Pro unlocks immediately.
Navigation: Settings → Upgrade to Pro
25.2 Restoring purchases
Reinstalling or changing devices: tap Restore Purchases; the app checks your store account's transaction history and restores Pro instantly.
Navigation: Settings → Upgrade to Pro → Restore Purchases
26. Platform Differences
Navigation is identical on both platforms. The following are genuine native divergences (by design — never "fixed" by cloning).
A. Permanent native divergences
| Area | iOS | Android |
|---|---|---|
| Watch | Apple Watch — 6 tabs (Hold/Wind/Card/Range/Hunt/Match) | Wear OS — 2-page mirror + hold picker |
| Home-screen widgets | 7 WidgetKit widgets | 1 Glance widget |
| Live Activity / Dynamic Island | yes | none (no equivalent API) |
| In-car | CarPlay (ships inert pending Apple's maps entitlement) | Android Auto (not implemented) |
| Voice | Siri + 7 App Intents | none |
| Live weather | WeatherKit | OpenMeteo |
| Cloud backup | iCloud (CloudKit + manual JSON) | SAF → Google Drive / Dropbox / OneDrive / local |
| Community auth | Sign in with Apple + email/password | email/password (same account) |
| On-device AI | rule-based + optional Apple Foundation Models (iOS 26+) | rule-based only |
| LiDAR Target Capture | yes (hardware) | none |
| Theming | Force Dark Mode | 4-theme picker |
B. iOS-only field tools (Android port in progress)
Fire Bans & Public Lands and Shooting Range Finder currently ship on iOS; the Android ports are in progress. Everything else in §9 is on both platforms.
C. Genuinely open — decisions, not code gaps
- Engine-data provenance — the Anti-Materiel minimum-caliber/energy and Barrier retention values, and four 6DOF aero "typical range" hint numbers, ship without cited sources and differ slightly between platforms; reserved for the engine-data owner to source and reconcile.
Both apps are at functional parity except for the native divergences above.
27. Appendices
Appendix A — Glossary of ballistic terms
- Ballistic Coefficient (BC) — a dimensionless number expressing how well a bullet overcomes air resistance relative to a standard projectile. Always tied to a drag model.
- Drag model (G1, G2, G5, G6, G7, G8, GI, GL, GS) — a standardized Cd-vs-Mach reference curve the BC scales. G1 is the oldest and most widely published (flat-base reference); G7 better models modern long-range boat-tail bullets.
- Cd (drag coefficient) — the dimensionless aerodynamic drag coefficient at a given Mach number. Custom drag curves express bullet-specific Cd-vs-Mach data.
- MOA / MIL / IPHY — angular units. 1 MOA ≈ 1.047″ at 100 yd; 1 MIL = 3.438 MOA; IPHY is "inch per hundred yards."
- DOPE — "Data On Previous Engagements" — your recorded real-world holds.
- Zero — the range and conditions at which point of impact equals point of aim with no holds. All corrections are offsets from this reference.
- Spin drift — gyroscopic lateral drift; right-hand twist drifts right, left-hand drifts left. Hemisphere-independent.
- Coriolis effect — deflection from Earth's rotation, depending on latitude, azimuth, and time of flight. In the Northern Hemisphere it deflects to the right of travel; in the Southern, to the left.
- Eötvös effect — the vertical component of Coriolis for east/west travel.
- Aerodynamic jump — a small crosswind-induced vertical deflection of the bullet path.
- Density altitude (DA) — pressure altitude corrected for temperature/humidity; the combined air-density effect on drag.
- Transonic / subsonic — roughly Mach 1.2–0.8, where drag becomes nonlinear and bullets can destabilize (color-coded in tables and overlays).
- Maximum Point Blank Range (MPBR) — the furthest range a bullet stays within a vital-zone height without a hold correction.
- WEZ (Weapon/Wind Error Zone) — a Monte-Carlo hit-probability estimate (P50/P90/P95 miss radii).
- SDF / DSF — Speed-Dial / Drop-Scale factors for adjusting dialed positions across density altitudes.
- Truing — fitting the ballistic model to observed drop (via MV, BC, or DSF).
- Sg (gyroscopic stability factor) — Miller stability; below ~1.3 is marginal, below 1.0 the bullet tumbles.
- CEP (Circular Error Probable) — the radius containing 50% of shots.
- ES / SD — extreme spread and standard deviation of a velocity string.
- Sectional density — bullet weight divided by the square of its diameter; higher generally penetrates better.
- TOF — time of flight, muzzle to target.
- CoT (Cursor-on-Target) — the XML message format used by TAK networks.
Appendix B — Supported drag models
| Model | Reference projectile | Best for |
|---|---|---|
| G1 | Flat-base, round nose (19th-century standard) | Most factory-ammunition BCs (widely published) |
| G2 | Aberdeen J projectile (ogival nose) | Some specialty projectiles |
| G5 | Short boat-tail, small-arm model | Moderate boat-tail bullets at intermediate range |
| G6 | Full flat-base, small caliber | Varmint and flat-base target bullets |
| G7 | Long-range boat-tail | Modern high-BC VLD/Hybrid designs (preferred for LR) |
| G8 | Flat-base, short ogive | Some military projectiles |
| GI | Flat-base military reference | Legacy military ball |
| GL | Lead round ball | Muzzleloaders, air pistols |
| GS | Short ball | Shotgun slugs and short-ball projectiles |
| Custom | User-defined Cd vs. Mach | When radar or two-chrono data is available; maximum accuracy |
| Measured (Doppler) | Factory radar-measured | Eliminates BC approximation entirely |
Recommendation by use case: factory hunting ammo — published G1 BC as a start, then true at long range; match bullets (Berger, Sierra, Lapua, Nosler RDF) — G7 BC; Lapua bullets — measured Doppler curves; reloads without a published G7 — derive your own with the BC Back-Calculator (§7.7).
Appendix C — Unit conversions quick reference
| Angular | MOA | MIL | cm/100m | in/100yd |
|---|---|---|---|---|
| 1 MOA | 1.000 | 0.291 | 2.909 | 1.047 |
| 1 MIL | 3.438 | 1.000 | 10.000 | 3.600 |
| 1 in/100yd | 0.955 | 0.278 | 2.778 | 1.000 |
| 1 cm/100m | 0.344 | 0.100 | 1.000 | 0.360 |
| Distance | meters | feet |
|---|---|---|
| 1 yd | 0.9144 m | 3.000 ft |
| 1 m | 1.0936 yd | 3.281 ft |
| 1,000 yd | 914.4 m | 3,000 ft |
| 1,000 m | 1,094 yd | 3,281 ft |
| Pressure | hPa/mbar | mmHg | kPa |
|---|---|---|---|
| 1 inHg | 33.864 hPa | 25.400 mmHg | 3.386 kPa |
| Standard sea level | 1013.25 hPa | 760.0 mmHg | 101.325 kPa |
Appendix D — Solver comparison
| Feature | 3DOF | 4DOF | 6DOF | Pejsa |
|---|---|---|---|---|
| Type | Numerical (RK4) | Numerical (RK4) | Numerical (RK4) | Analytical |
| Spin drift | Empirical | Physics-derived | Physics-derived | Not included |
| Aerodynamic jump | Empirical | Physics-derived | Physics-derived | Not included |
| Spin-rate tracking | No | Yes (4th DOF) | Yes | No |
| Rotational dynamics | No | No | Full 6-axis | No |
| Speed | Fast | Moderate | Slow | Instant |
| Best for | General field use | VLD/Hybrid bullets | Research | Quick estimates |
Recommendation: 3DOF for the vast majority of field and competition use; 4DOF when you need physics-derived spin drift and aerodynamic jump for VLD/Hybrid bullets; 6DOF for research; Pejsa for an instant answer when you don't need spin-drift corrections (it ignores wind, Coriolis, spin drift, jump, and inclination).
Appendix E — Coriolis and spin drift: directionality
Both introduce lateral deflection that matters at extended ranges.
- Coriolis (Northern Hemisphere): deflects bullets to the right of travel relative to the shooter; firing east/west is primarily the vertical Eötvös effect. In the Southern Hemisphere it deflects left.
- Spin drift: right-hand twist drifts right, left-hand twist drifts left — always, regardless of hemisphere.
At 1,000 yards each effect can be 0.2–0.5 MIL, and they can add or oppose depending on latitude, azimuth, and twist direction. The app accounts for both independently.
Appendix F — Real counts
| Item | Count (both platforms unless noted) |
|---|---|
| Bullet database | 3,715 |
| Reticle library | 2,971 |
| Cartridge database | 152 (11 categories) |
| Pellet database | 674 |
| Standard drag models | 9 (G1 G2 G5 G6 G7 G8 GI GL GS) + custom |
| Solvers | 4 (3DOF / 4DOF / 6DOF / Pejsa) |
| Vital-zone presets | 15 |
| Automated engine/data tests | 191 (iOS engine) |
| Training-Academy drills / pillars | 60 / 6 |
| Training-Academy glossary | 299 |
| Concept lessons / training plans | 14 / 2 |
| Anti-Materiel target classes | 10 |
| Barrier-penetration types | 12 |
| Home-screen widgets | iOS 7 · Android 1 |
| Free-tier rifle limit | 3 |
Appendix G — Privacy and data security
- On device: all profile, shot-log, and inventory data is stored locally in the app's protected data container. TAK received events are encrypted at rest (AES-256-GCM / complete file protection). TAK certificates and credentials are stored in the OS keychain/keystore.
- Transmitted: live weather location (to Apple WeatherKit / OpenMeteo); cloud-sync data (iCloud/CloudKit on iOS); TAK solutions and positions (to your configured TAK server only); anonymous diagnostics. No data is ever sold or shared with advertisers.
- Location: used only for weather queries, Coriolis latitude auto-fill, GPS ranging, and shooting-light calculations — requested only when you tap a "use my location" control.
Canonical guide — supersedes the standalone iOS and Android drafts and the former FEATURES.md. Document current as of 2026-06-21; features are subject to change.
