AR-9 Builder

Over 1 million parts configured since 2020

Build a 9mm AR-9 pistol or carbine part by part and price it in real time. Pick a 9mm lower, then the upper, barrel, blowback bolt, buffer, handguard, trigger and optic. GunPartPicker flags 5.56 barrels and bolts that do not match a 9mm lower and compares live prices across 10+ retailers so you can see what the full build costs before you buy.

Not sure where to start? The AR Build Cost Calculator fills every slot with the part builders add most, in stock, and prices the whole build.

Choose a part to start your build

Build an AR-15, AR-10 or AR-9

AR-15 Builder

Build a 5.56 NATO, .223 Wylde, 300 Blackout or 6mm ARC AR-15 on a standard small frame lower, with compatibility checked on every slot.

AR-10 Builder

Build a .308, 7.62 NATO or 6.5 Creedmoor AR-10 the same way. Start with a large frame lower and the builder flags any small frame upper, barrel or bolt carrier group that will not fit it.

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