Terminology

A quick, plain-language glossary of the terms you will see in Precision Arrow Builder.

FOC (front-of-center)

A measure of how far an arrow's balance point sits toward the front, given as a percentage. It describes where the weight is distributed along the arrow.

GPI (grains per inch)

How much a shaft weighs per inch of length, in grains. It is commonly used to compare shafts and to estimate a shaft's contribution to total arrow weight.

Community catalog

A shared collection of component information contributed by other users. You can sync entries from it into your own component catalog to save time getting started. Submissions receive a basic review before they are accepted, but that review is not exhaustive and entries are not promised to be error-free, so always verify important component specifications before relying on them. You are welcome to contribute your own components, or corrections to existing ones.

Component catalog

Your personal list of the components you build with — shafts, points, inserts, nocks, fletching, and so on — along with the details you record for each one. Think of it as your reference library of parts.

Component inventory

What you actually have on hand: how many of each component you own and their measured weights. Inventory is the measured data the app uses to help you plan a consistent set.

Arrow set

A group of arrows built to be as alike as practical — for example a dozen arrows for indoor target. Building a consistent arrow set is the core goal of the app.

Measured component

A component whose real, weighed details you have recorded, rather than relying on a published or estimated value. Measured components are the foundation for consistent results.

Optimization

Letting the app help you choose which measured inventory components to combine so the arrows in a set are as consistent as practical — for example by keeping weight and FOC differences small.

Extreme spread

The difference between the highest and lowest value in a group — for example the heaviest arrow minus the lightest. It is a simple way to describe the full range of variation in a set.