Project status
Last updated 20 October 2026 · Under active development
PewBuild is being built in the open. It works, it is useful today, and it is unfinished in ways worth being specific about — because a tool that tells you what it does not know is more useful than one that pretends.
What works now
- A real compatibility engine. Pick components and it checks interface fit, dimensional clearance and functional advisories against recorded specifications — barrel extension to upper, gas length to gas tube, thread pitch to muzzle device, handguard length against barrel length, and the chamber-to-cartridge relation that matters most.
- Over 2,200 real components from more than 68 manufacturers, each carrying the page its specification came from and the date it was read.
- A 3D view that assembles as you choose, built from the actual recorded dimensions, with assembled and exploded views.
Why parts are missing
The catalog is assembled by automated collection from manufacturers' own published pages. That scales to tens of thousands of products, and it inherits every gap in the source: a maker who does not publish a journal diameter leaves that field empty, a page behind a bot wall is not read at all, and some manufacturers decline automated access entirely and are therefore absent.
So coverage is uneven, and it is uneven in ways that are not always obvious. If a part you want is missing, it is far more likely an unread page than a deliberate omission.
Where a specification was never published, the fit report says the check could not run rather than guessing. An unrecorded value never reads as compatible. That is the core discipline of the project and it will not be traded away for a tidier-looking result.
Why there are no product photographs
This one is a deliberate choice, not a gap in the data.
A specification is a fact — a thread pitch is 1/2x28 no matter who writes it down. A product photograph is a creative work owned by whoever made it. Those two things sit side by side on every product page, and treating them the same way would mean republishing other people's photography without permission. We have not done that, and will not.
So every part is currently shown as a parametric illustration and labelled "No product photo", which is the honest label for what you are looking at. The illustration is built from the part's real recorded dimensions — a 16″ barrel is drawn longer than a 10.5″ one — but it is a drawing of a configuration, not a picture of that exact product.
The route to real photographs is a licensed product feed, where the imagery comes with permission to display it as part of the agreement. Those applications are in progress. The moment one is approved, the parts it covers will show actual photographs, and the label will change to say so.
Known gaps, plainly
| Area | Where it stands |
|---|---|
| Product photography | None. Awaiting a licensed feed. |
| Part coverage | Uneven. Strong on barrels, handguards, uppers; thin on gas blocks, triggers, buffers. |
| Specification completeness | Many real parts have gaps where the maker did not publish a value. These report as unknown. |
| Legal compliance | Implemented but unreviewed. The engine refuses to issue a clean compliance verdict and says so. Not legal advice. |
| 3D fidelity | Illustrative. Proportions are real; surfaces and markings are not. |
| Platforms | AR-15 only. Large-frame and other platforms are modelled in the data but not yet selectable. |
| Accounts and saved builds | Builds save to your own browser only. No accounts, no cloud. |
Ask for a part or a feature
This is the most useful thing you can do, and requests genuinely drive what gets built next.
Email admin.pewbuild@gmail.com with:
- A missing part — the maker, the model, and a link to its page. A link makes it quick to add properly, with its source recorded like everything else.
- A wrong specification — what the site says, what the manufacturer says, and the page you are reading. Every record carries its source, so these are fast to verify and correct.
- A feature — what you were trying to do and where the tool got in the way. That is more useful than a solution, because it leaves room for a better one.
- A platform — if you want something other than AR-15 supported, say which and what you build.
If you make or sell these parts
Corrections are welcome and fast. Removal requests are honoured without argument. And if you can supply a product feed, that is the single thing that would most improve this tool for the people choosing your components — accurate specifications, current pricing, and photography we are permitted to show. See contact.
Thanks for using something that is still being built.