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Tools in the app

The tools, and how they work.

Some jobs need a screen of their own: measuring a group, scoring a card, truing your BC or checking a load. dopeology has a tool for each. Here’s how they work.

Calculators

Stability Calculator

Will your twist rate stabilise that bullet? Don Miller’s twist rule, corrected for the temperature and air you shoot in.

How it works

  1. Choose a projectile, or type its weight, diameter and length, then add muzzle velocity and barrel twist.
  2. Add the temperature and either altitude or station pressure, or load a saved rifle to fill everything in.
  3. Read the stability factor (Sg): under 1.0 is unstable, 1.0 to 1.5 is marginal, 1.5 and over is comfortably stable.
  4. See the slowest twist that reaches 1.5, and the longest bullet your barrel will hold.

Miller’s rule is calibrated on boat-tail match bullets, and doesn’t apply to airgun pellets.

Read the full guide

Muzzle Energy Calculator

Energy from a velocity and a projectile weight. Handy for checking a sub-12 ft-lb airgun, an FAC limit or a minimum energy for quarry.

How it works

  1. Enter the muzzle velocity in fps or m/s.
  2. Enter the pellet or bullet weight in grains or grams.
  3. Read the energy in ft-lb or joules as you type.

For the energy carried downrange, add the Energy column to your DOPE Card.

Read the full guide

Unit Convertor

The conversions shooters juggle, without leaving the app.

How it works

  1. Type a value into any field and read the equivalents alongside it.
  2. Distance, length, weight, velocity, energy, wind speed, pressure and temperature are all covered.
  3. Scope Adjustment converts MOA, mrad or clicks into the size they cover at a given range, and back: “5 cm low at 200 m” becomes a correction you can dial.
Read the full guide

Measuring & scoring

Group Analyser

Measure a shot group from a photo of your target. No ruler at the bench.

How it works

  1. Take or choose a photo of the target and crop it to the target area.
  2. Set the scale from a known length on the target, such as a grid square or its printed size.
  3. Mark your point of aim, then tap each shot hole and drag to fine-tune.
  4. Read the group size and statistics, export an image of the result, and save it against a profile, target or load.

Your saved groups also feed the Group Analysis widget.

Read the full guide

Bench Rest Scorer

Score a multi-bull bench rest card from a photo. The AGF BR20 card is built in, and you can add your own.

How it works

  1. Pick the scoring system, the bullet calibre used for gauging, and whether to include sighters.
  2. Photograph the card and drag four corners onto the outer targets to line up the grid.
  3. Check the rings sit on every bull, then tap where each shot hit.
  4. Get the total, X count and a per-target table, ready to export as an image or copy as a table.

Design your own cards (ring sizes, targets per card, sighters) in the Bench Rest Target Editor.

Read the full guide

Calibration & analysis

BC Calibrator

Fit your bullet’s ballistic coefficient to the drops you actually measured, so the solver matches your rifle.

How it works

  1. Log shots with their measured drop in a session.
  2. Tap Calibrate under the Truing Table widget, or at the foot of the session.
  3. Choose a mode: Scalar scales the whole BC, Segmented tunes each velocity band, and Propose builds new bands from your data.
  4. Compare the current and fitted BC, the error and the drop table, then apply it to your profile or save it as a new projectile.

Chronograph your load first: a wrong muzzle velocity looks just like a wrong BC. On the web, the calibrator is part of Cloud-Sync.

Read the full guide

Sensitivity Analysis

Find out which inputs matter at your range: how far the point of impact moves if velocity, BC or the conditions are a little off.

How it works

  1. Pick the rifle and location, and set the range with the dial.
  2. Choose the inputs to test, such as velocity, BC, temperature and pressure, and how much to change each by, in your own units.
  3. Read the shift for each one, both as a dial correction and as a distance on the target.

Every solve re-zeros, so each figure is the true shift at range for the same zero. On the web, it’s part of Cloud-Sync.

Read the full guide

Projectile Comparison

Two bullets from the same rifle, zero, air and wind, so any difference is down to the bullets alone.

How it works

  1. Projectile A starts as your current load; pick B from the library or your own projectiles.
  2. Optionally give either one a different muzzle velocity, without touching your saved load.
  3. Compare drop, velocity or energy on a chart and in a side-by-side table, against range or time of flight.
Read the full guide
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