The AR-15 Build Cost Index

Parts pricing on this platform moves constantly, and almost every published figure about what an AR costs is a snapshot from whenever somebody wrote it down.

This one is not. The numbers below are computed from live in-stock offers across the retailers we track and rewritten every morning.

Today's index

Three figures, and the third is the interesting one.

Budget build is the sum of the cheapest genuinely in-stock offer in each core slot. It is a floor, not a recommendation, and hitting it requires buying from whoever happens to be cheapest in every category at once.

Typical build is the sum of the median price in each slot. This is closer to what a normal person actually pays, because nobody optimises every slot.

The spread between them is what shopping around is worth. When the spread widens, patience pays. When it narrows, the market is tight and waiting gains you little.

What the index covers

Ten core slots: lower receiver, upper receiver, barrel, bolt carrier group, handguard, trigger, stock, pistol grip, charging handle and buffer tube assembly.

That is a functioning rifle and nothing more. It deliberately excludes optics, sights, lights, slings, magazines and ammunition, because those vary enormously with intent and would make the index meaningless as a comparison over time.

Budget separately for those. Our cheapest complete build guide covers what they add.

How the figures are calculated

Two decisions matter and both are deliberate.

In-stock only. An offer nobody can fill is not a price. Out of stock listings are excluded entirely, which is why this index can move upward when availability tightens even if nothing has been repriced.

Percentiles, not extremes. The catalog contains mispriced and mislabelled rows, and the absolute cheapest listing in a category is usually one of them rather than a genuine deal. The budget figure uses the tenth percentile of in-stock offers, which is a floor you can actually buy at.

Categories with too few offers to be meaningful are skipped rather than published thin.

Reading movement over time

A few things move this index, and distinguishing them is useful.

Supply. When stock tightens, the cheap end disappears first. The budget figure rises before the typical figure does, and the spread narrows. That is the clearest early signal of a constrained market.

Genuine repricing. Both figures move together. Slower, and usually driven by input costs or demand.

Sales events. The budget figure drops sharply while the typical figure barely moves, widening the spread. Our Black Friday guide covers what actually discounts and what does not.

What it does not tell you

This is a parts index, not a value judgement. A build at the budget figure and a build at the typical figure are not the same rifle, and the difference is concentrated in the slots that matter most.

As our build order analysis sets out, the barrel and bolt carrier group are where cheapness costs you, and they are also two of the slots with the widest price range. A build that hits the budget number by economising there is a worse rifle than the figure suggests.

Use the index to time your purchase, not to decide what to buy.

Building versus buying complete

The question this index raises for most people is whether building is actually cheaper than buying a finished rifle, and the honest answer is: often not, and that is fine.

A factory rifle is assembled at volume with parts bought at volume. At the budget end of the market, a complete rifle frequently undercuts the sum of its parts, because you are competing with a manufacturer's purchasing power using retail pricing.

What building buys you is control. You choose the barrel, the trigger, the handguard length and the gas system rather than accepting somebody else's compromise, and you learn how the rifle works while assembling it. At the middle and upper end, where factory rifles carry a brand premium, building also starts to win on cost.

Compare the index against complete rifles in the same bracket before assuming that building saves money. If it does not, build because you want the rifle you want.

How to actually use this page

Check it before committing to the expensive slots rather than reading it once.

Barrels and complete uppers swing considerably with stock levels. Grips and small controls barely move. So buy the stable cheap parts whenever suits you, and watch this page for the two or three slots where timing is worth real money.

A barrel bought during a dip can cost meaningfully less than the identical barrel a few weeks later, and that difference is usually larger than everything you could save by economising across every small part combined.