The Ultimate Online
Gun BuilderOver 1 million parts configured since 2020
Build your AR platform part by part, compare live prices from 10+ retailers, check compatibility as you go, and share the exact build. Real builds power our parts guides, and every brand and ammo caliber we track is priced daily.
Today's Popular Products
Popular products in the past 24 hours.
Popular Builds
Featured AR-15 builds from the community.
Build Guides From Real Data
What real builds say about the parts people actually run, ranked by brand, price and popularity. Updated as the builds come in.
- AR-15 Trigger Popularity Report: What 15,000+ Builders Are Pulling
Data from 15,000+ real AR-15 builds reveals which triggers builders prefer. Geissele leads, with Rise Armament and Timney close behind.
10 min read - The Most Trusted AR-15 BCGs: A 15,000-Build Data Analysis
Data from 15,000+ real AR-15 builds reveals which bolt carrier groups builders prefer. Aero Precision and PSA lead, but coating choice tells the real story.
10 min read - Most Popular AR-15 Upper Receivers: Data-Backed 2026 Guide
Data from 15,000+ real AR-15 builds reveals which upper receivers builders trust. BCM leads, with Aero and Geissele close behind.
10 min read - AR-15 Lower Receiver Trends: 15,000+ Builds Analyzed
Data from 15,000+ real AR-15 builds reveals which lower receivers builders trust most. Aero Precision M4E1 dominates, but PSA and Radian carve strong niches.
10 min read - AR-15 Barrel Length & Brand Report: Data from 15,000+ Builds
Choosing the right barrel length is one of the most impactful decisions in an AR-15 build. This guide breaks down velocity, dwell time, gas system compatibility, and real-world handling across every common barrel length from 10.5" to 20".
12 min read - AR-15 Handguard Trends: What 15,000+ Builders Installed in 2026
Data from 15,000+ real AR-15 builds reveals which handguards builders prefer. TacFire leads volume, but Daniel Defense and Midwest Industries dominate the mid-range.
10 min read
Shop by Brand
Twelve of the 587 brands we track, ranked by live inventory. Each brand page lists every product we price, which retailers carry it, what builders actually add to their builds, and how much of the catalogue is in stock right now.
Ammo Prices Today
Cheapest in-stock cost per round across every merchant we track, updated daily.
What is GunPartPicker?
GunPartPicker is a modern online gun builder and parts comparison platform designed to help you build smarter. Create a virtual build, organize your components, and compare real-time pricing from trusted online retailers — all in one place.
Whether you're planning a full AR-15 build or researching individual components, GunPartPicker replaces spreadsheets, paper lists, and guesswork with a clean, shareable build system.
Build, Compare, and Customize Your AR-15 with Confidence
Filterable Categories
Part lists are broken out by filterable categories to ensure you include all the necessary components.
Updated Pricing
Continuously updated prices from several of the most popular online retailers.
Easy Sharing
Easy sharing through text, email & social media.
Ready to Assemble Your Perfect Rifle?
Gun builders use this tool every single day to assemble smarter, cheaper, and more accurate builds.