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Upper Receivers Guides

Stripped and assembled receivers, forgings, billet, and specs.

8 guidesUpdated monthly
Close-up of an AR-15 dust cover installed on the ejection port of a rifle.
FeaturedUpper Receivers

What It Does and Why It Matters - AR-15 Dust Cover Guide

What does an AR-15 dust cover do? Learn how it works, what parts it uses, and when to replace it. Shop dust covers at AR15Parts.com. Call (888) 706-0633.

Aug 7, 2026·9 min read
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More Upper Receivers Guides

Three AR-15 barrels laid side by side on a dark surface: polished stainless, matte black nitride, and grey chrome-lined.
Upper Receivers

Chrome-Lined vs. Nitride vs. Stainless AR-15 Barrels

How chrome-lined, nitride, and stainless AR-15 barrels differ on accuracy, barrel life, cost, and maintenance, and which one is right for your build.

Jul 21, 2026·8 min read
Close up macro view down an AR-15 barrel bore showing the spiral rifling grooves.
Upper Receivers

AR-15 Twist Rate Guide: 1:7 vs. 1:8 vs. 1:9 Explained

How AR-15 barrel twist rate works, what 1:7, 1:8, and 1:9 actually do, and how to match twist rate to the bullet weight you plan to shoot.

Jul 14, 2026·7 min read
Top-down exploded flat lay of AR-15 upper receiver group components on a dark walnut workbench: receiver, BCG, charging handle, barrel, gas block, gas tube, handguard, and muzzle device.
Upper Receivers

AR-15 Upper Receiver Anatomy: Every Part Explained

A complete AR-15 upper receiver parts list with a plain-English explanation of what each part does, how it interacts with the rest of the group, and where it commonly fails.

Jul 11, 2026·8 min read
A billet AR-15 upper receiver with angular machined lines beside a rounded mil-spec forged upper on dark slate.
Upper Receivers

Billet vs. Forged AR-15 Upper Receivers: What Actually Matters

Billet vs. forged AR-15 upper receivers compared: how they're made, strength differences, cost, aesthetics, and which one is right for your build.

Jul 11, 2026·6 min read
Mil-spec and commercial AR-15 buffer tubes side by side with calipers on dark slate.
Upper Receivers

Mil-Spec vs. Commercial AR-15 Parts: What the Difference Actually Is

Mil-spec vs. commercial AR-15 parts explained: where the difference actually exists (mainly buffer tubes), where it's just marketing, and what to buy.

Jul 11, 2026·6 min read
Complete AR-15 upper receiver with 16-inch stainless barrel and free-float M-LOK handguard on dark slate.
Upper Receivers

AR-15 Upper: The Complete Guide to Upper Receivers, Calibers, and Builds

The definitive pillar guide to AR-15 uppers, anatomy, stripped vs. complete, caliber options, legal classification, installation, and matching an upper to your use case.

Jul 10, 2026·13 min read
A stripped AR-15 lower receiver with pistol grip on a dark workbench next to a legal document and pen.
Upper Receivers

Is an AR-15 Upper Considered a Firearm?

Under federal law, the AR-15 lower is the serialized firearm, not the upper. Here's what that means for buying, shipping, and background checks.

Jul 10, 2026·7 min read