GunPartPicker: A PCPartPicker for Guns

Is There a PCPartPicker for Guns?

Yes, and you're on it. GunPartPicker lets you plan an AR-15, AR-10, AR-9 or Glock build part by part, compare prices from 35+ retailers, catch parts that won't fit, and share the finished list with one link.

You don't pay anything, and you don't need an account. We built it because PC builders have had PCPartPicker for over a decade while gun builders were stuck with spreadsheets and twenty open tabs.

As of October 2026 we carry 120,000+ products from 770+ brands across 130+ categories, and 44,000+ of them are in stock right now.

What's Built In

Here's what you get the first time you open the builder:

✓ Slot by slot builders for AR-15, AR-10, AR-9 and Glock ✓ Live prices from 35+ firearms retailers, side by side ✓ 44,000+ products in stock and tracked ✓ Compatibility checks for platform, caliber, gas system, thread pitch, rail interface and scope tube size ✓ Shareable build links you can post anywhere ✓ A running total that updates every time you swap a part ✓ Search and filters by brand, price and specs across 770+ brands ✓ Ammo price hubs for 55 calibers with live cost per round ✓ No account needed to build, compare or share ✓ Works on your phone and your desktop ✓ A free account if you want your builds on every device

How the Builder Works

If you've used PCPartPicker, you'll feel at home in about ten seconds. If you haven't, you'll still be fine.

Each slot holds one part of your rifle. Click a slot, search or browse that category, and pick a part. It drops into your build, the total updates, and we check it against everything you've already picked before you move on.

A full AR build takes most people about five minutes. The Glock builder works the same way with its own slots, from the slide, barrel and frame to the trigger, sights, optic plate, magazine and holster.

Here's how the AR builder slots break down.

Receivers and Barrel

Lower Receiver is where you start. It's the serialized part, so legally it's the firearm, and it locks in your platform: AR-15, AR-10 or AR-9. Every check after this point references the lower.

Upper Receiver has to match your lower's platform. You can't put an AR-10 upper on an AR-15 lower, and we'll tell you before you try.

Barrel sets your caliber, your accuracy ceiling and your gas system length. We carry 5,000+ barrels, so you'll find the length and profile you're after.

Bolt Carrier Group has to match your barrel's caliber. Run a 5.56 BCG with a 5.56 barrel, a .308 BCG with a .308 barrel, and a 9mm BCG with a 9mm barrel.

Internals

Trigger comes as a single stage, a two stage or a drop in cassette. You'll feel a trigger upgrade more than any other part you swap on an AR.

Charging Handle comes standard or ambidextrous. An ambi handle costs a little more and lets you run the rifle from either side.

Gas Block is low profile or adjustable. An adjustable block lets you tune the rifle so it runs right both suppressed and unsuppressed.

Furniture and Muzzle

Handguard has to clear your gas block and fit your barrel nut. M-LOK won the rail wars, and you'll see it on almost every new handguard we list.

Stock comes fixed, collapsible or adjustable. Match it to your buffer tube, because mil-spec and commercial tubes aren't the same diameter.

Pistol Grip is pure preference. A2, K2, vertical, whatever fits your hand.

Muzzle Device thread pitch has to match your barrel: 1/2x28 on most 5.56 barrels and 5/8x24 on most .308 barrels. We flag a mismatch the moment you add one.

Accessories

Optics, lights, slings, backup sights and magazines all get their own slots. Optics alone run deep, with 3,700+ rifle scopes and 6,500+ mounts, and we check your scope's tube diameter against the mount you pick.

Price Comparison from 35+ Retailers

Price comparison saves you more money than anything else on the site. This week a Geissele G2S trigger sat at about $148 at the cheapest of the 12 stores that had it in stock and $180 at the priciest. You'd pay $32 extra just for clicking the wrong tab.

We pull prices from 35+ retailers and line them up for every product we carry. You see the price, the stock status and where to buy it, all on one page.

Your build keeps a running total. Swap the barrel and the total moves. Try a different trigger and you'll see the difference instantly, so you can price three builds in the time it takes to price one by hand.

Compatibility Checking

PCPartPicker won't let you drop an AMD chip into an Intel board. We do the same job for gun parts.

Critical checks catch parts that physically won't work together:

• Platform mismatch (an AR-10 upper won't fit an AR-15 lower)
• Caliber mismatch across the upper, barrel and bolt carrier group (a .308 bolt won't run in a 5.56 upper)

Warnings flag parts that might give you trouble:

• Gas system length between the barrel and the gas tube (carbine, mid length, rifle or pistol)
• Thread pitch between the barrel and the muzzle device (1/2x28 vs 5/8x24)

Fit notes cover the smaller stuff:

• Mounting interface (M-LOK, Picatinny, KeyMod)
• Scope tube diameter against your mount (30mm, 34mm and so on)

We'll warn you, but we won't block you. Sometimes you know exactly what you're doing. A .300 BLK upper on a 5.56 lower runs fine, because the lower doesn't care about caliber.

The warnings catch real mistakes without getting in an experienced builder's way.

Shareable Build Links

Your build lives in its link. Copy it, text it to a buddy, drop it in a forum thread or save it in your notes. Whoever opens it sees your exact parts list with today's prices.

You'll never type a parts list into a forum post again. Post the link and people see what you've got, then they can start their own version from yours.

Builds save to your browser on their own. Sign in and they follow you to every device. Close the tab, come back next week, and your build will still be waiting.

Sample Builds

We put together three starting points. Every part comes from our catalog, so you can load one up and start swapping.

Budget Build ($600 to $800)

Start with a PSA or Aero lower, an Aero upper, a 16" mid length barrel, and a standard BCG and charging handle. Add a Sig Romeo 5 and a sling. It runs, and it leaves you room to upgrade later.

Mid Range ($1,200 to $1,500)

Put a quality barrel in a BCM or Aero upper, then add a Geissele or LaRue trigger, a Radian charging handle and a Holosun or Sig optic. You buy once and cry once, and you won't think about this rifle again for thousands of rounds.

Full Send ($2,000+)

Go with a KAC, LMT or Daniel Defense upper, a Geissele trigger, an Aimpoint or EOTech, and a SureFire light. Every part earns its slot. Build this one when you want a single rifle done right and never want to revisit it.

The Catalog by the Numbers

Here's what we track as of October 2026:

Optic mounts lead the AR side with 6,500+ listings. Upper receivers (5,200+), barrels (5,000+), rifle scopes (3,700+), handguards (3,600+), muzzle devices (3,500+) and lower receivers (2,100+) follow.

The catalog has roughly quadrupled since March. The Glock builder and the ammo price hubs brought in a big share of that, and the AR side kept growing too.

Why This Took So Long to Build

PC parts come with standard sockets, standard form factors and a handful of big retailers. Gun parts don't.

Dozens of small, specialized retailers sell the parts. Pricing them means pulling feeds from 35+ stores, and every store runs its own catalog and its own stock system.

Compatibility rules come with exceptions. Caliber families, gas lengths, thread pitches, rail interfaces and platform generations all interact. A .300 BLK runs on a 5.56 bolt but not in a 5.56 barrel.

An AR-10 lower from one maker might not mate with an AR-10 upper from another, because DPMS and SR-25 patterns differ.

The product space keeps growing. We now carry 770+ brands across 130+ categories. Barrel makers alone sell dozens of SKUs each across lengths, profiles, gas systems and calibers, and every one has to land in the right slot with the right specs before the compatibility checks can trust it.

Start Building

Open the AR builder or the Glock builder and pick your first part. It's free, it works on your phone, and you won't need an account. We add products and retailers every day, so check back when you're planning the next one.