Shop All Gun Parts: The Complete Builder’s Directory

Welcome to the most comprehensive parts directory for the private firearm builder. This is your central hub for sourcing every component, from the smallest spring and detent to a complete slide assembly. A successful build depends on quality, compatible parts. We’ve eliminated the guesswork by organizing our entire inventory of vetted, high-performance hardware right here. Whether you are upgrading, repairing, or starting a build from scratch, this is where your project begins.

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Your Guide to Firearm Components

Understanding how parts are categorized is key to finding what you need quickly. We’ve organized our inventory into logical systems based on firearm platform and function.

• Platform-Specific Parts: Components designed exclusively for a specific firearm, like a G19 slide or an AR-15 lower parts kit.
• Universal Components: Parts that can be used across multiple builds, such as grips, optics, or certain springs.
• Completion Kits: Bundled parts designed to finish a specific project, like an 80% frame or a 3D printed receiver.

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Browse All Parts by Firearm System

(This section is the core of the page. It uses large, clickable visual cards or text blocks for clear navigation to the more specific sub-categories.)

 Pistol Parts & Components

This is your source for everything needed to build or upgrade a Glock-style handgun. Find slides, barrels, frame parts, and the critical rail hardware for 3D printed builds. We focus on parts compatible with the G19, G17, and other popular platforms.

• [Link] Complete Pistol Slides →
• [Link] Pistol Barrels →
• [Link] Pistol Lower Parts Kits (LPKs) →
• [Link] 3D Print Rails & Hardware →
  [Main Link Button] Shop All Pistol Parts →

 AR-15 & Rifle Parts

Everything you need for America’s most popular rifle platform. This collection includes high-quality 80% lowers, complete upper receivers, lower parts kits, buffer tube assemblies, and furniture to complete your AR-15, AR-9, or AR-10 build.

• [Link] 80% Lower Receivers →
• [Link] Complete Upper Receivers →
• [Link] Rifle Lower Parts Kits (LPKs) →
• [Link] Stocks, Grips & Furniture →
  [Main Link Button] Shop All AR-15 Parts →

 3D Print Hardware & Upgrades

Success in 3D printing requires more than just a printer. This section contains the essential hardware to make your machine a reliable production tool. Find hardened steel nozzles, all-metal hotends, and the high-strength filaments required for a safe build.

• [Link] High-Strength Filaments (PLA+, Nylon) →
• [Link] 3D Printer Nozzles & Hotends →
• [Link] Printer Upgrade Components →
  [Main Link Button] Shop All 3D Print Supplies →

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FAQ: Understanding Gun Parts

Q1: What is a Lower Parts Kit (LPK)?

A1: A Lower Parts Kit, or LPK, is a package containing all the small internal components needed to complete a stripped lower receiver. This includes the trigger assembly, hammer, safety selector, pins, and springs required for the firearm to function.

Q2: What is the difference between a stripped upper and a complete upper?

A2: A “stripped” upper receiver is just the bare aluminum housing. A “complete” upper receiver is a fully assembled unit that typically includes the barrel, handguard, bolt carrier group (BCG), and charging handle, ready to be attached to a finished lower receiver.

Q3: What are the most important parts to upgrade on a firearm?

A3: The most impactful parts to upgrade for performance are the trigger, barrel, and optics. A high-quality trigger improves accuracy and control, a precision barrel enhances mechanical accuracy, and a red dot sight allows for faster target acquisition. For a beginner’s guide on this topic, Pew Pew Tactical offers excellent articles on firearm upgrades.

Q4: Are all AR-15 parts interchangeable?

A4: The vast majority of AR-15 parts are interchangeable (mil-spec). However, there are two main piston/gas systems (direct impingement and piston) and different buffer weights that must be matched correctly. Additionally, AR-10/LR-308 parts are not interchangeable with AR-15 parts.

Q5: Is it legal to buy gun parts online in the USA?

A5: Yes, it is legal to buy unregulated gun parts like barrels, slides, LPKs, and upper receivers online and have them shipped directly to your home in the USA. The only federally regulated part that requires shipment to a licensed dealer (FFL) is the finished firearm frame or receiver itself.