AR-15 Complete Upper, 16″ 5.56 Carbine Barrel w/ Pinned FSB, MOE SL® Carbine

Product Overview

Build a rugged, no-frills AR-15 with the AR-15 Complete Upper 16″ 5.56 Carbine Barrel Pinned FSB MOE SL. This complete upper pairs a 16″ 5.56 NATO carbine barrel with a pinned front sight base (FSB) and the Magpul MOE SL® carbine-length handguard. It gives you a classic carbine profile with modern ergonomics, ready to mount straight onto your lower.

We machine every AR-15 Complete Upper, 16″ 5.56 Carbine Barrel w/ Pinned FSB, MOE SL® Carbine to mil-spec tolerances. It drops onto any mil-spec AR-15 lower for a tight, dependable fit.

Upper Features:

• Upper: Standard AR15 Upper Receiver
• Barrel: 16″ 5.56 Carbine Barrel w/ Pinned FSB
• Handguard: Magpul™ MOE SL® Carbine Handguard
• Gas System: Carbine Length Gas System
• Muzzle Device: Standard A2 Flash Hider
• This complete upper DOES NOT include a BCG and Charging Handle. You can add these items in the “FINISH YOUR BUILD” tab.

What Is the Upper Made Of?

Here’s what goes into this build:

• Receiver — We machine it from 7075-T6 aluminum for a strong, lightweight, fatigue-resistant build.
• Barrel — We build the 16″ carbine barrel from chrome-moly vanadium steel. It handles sustained fire well and holds up over years of use.
• Pinned FSB — The front sight base pins directly to the barrel, giving you a fixed front sight and a mounting point for a bayonet lug or sling swivel, in the classic carbine configuration.
• Finish — A hard-coat anodized finish protects the receiver and barrel from corrosion and wear.
• MOE SL® Carbine Handguard — Magpul builds this handguard from reinforced polymer over an aluminum heat shield. It gives you a slim, low-profile grip with accessory attachment points, without adding unnecessary bulk or weight.
• Gas System — A carbine-length gas system matches the 16″ barrel, delivering reliable cycling in a proven, well-tested configuration.

This combination makes the AR-15 Complete Upper 16″ 5.56 Carbine Barrel Pinned FSB MOE SL durable, dependable, and built for shooters who want a classic carbine setup that just works.

How to Install This Upper

Follow these steps to mount your new upper:

1. Check compatibility. Confirm your lower receiver is mil-spec and matches standard AR-15 uppers.
2. Remove the takedown and pivot pins on your lower receiver if needed.
3. Align the upper and lower. Line up the pivot pin lug on your lower with the matching hole on the upper.
4. Insert the pivot pin. Push it through to join the front of the upper and lower. The upper now pivots like a hinge.
5. Close the upper onto the lower until the two sit flush.
6. Insert the takedown pin through the rear of the receivers to lock them together.
7. Install the charging handle and bolt carrier group if they aren’t already in place.
8. Run a function check. With the rifle unloaded, cycle the charging handle and test the trigger before you head to the range.

Always confirm your firearm is unloaded before you start. Ask a qualified gunsmith for help if you’re new to firearm assembly.

How to Disassemble the Upper Receiver

Reverse the installation steps for cleaning or maintenance:

1. Clear the firearm. Confirm it’s unloaded and remove the magazine.
2. Remove the charging handle and bolt carrier group. Pull the charging handle back slightly, take out the bolt carrier group, then remove the charging handle fully.
3. Push out the takedown pin to separate the rear of the upper and lower.
4. Pivot the upper open on the front pivot pin.
5. Remove the pivot pin to fully separate the upper from the lower.
6. Remove the MOE SL® handguard if needed. Loosen the handguard’s mounting hardware to access the barrel and gas system for deeper cleaning.

Clean the bolt carrier group, chamber, and barrel after each use. Regular cleaning keeps this upper cycling reliably and extends the life of every component.

How to Buy This Upper

Follow these steps to order:

1. Check your state and local laws. Confirm upper receivers ship freely in your state before you order.
2. Choose your configuration. Confirm this 16″ carbine barrel, pinned FSB, and MOE SL® handguard match your build goals.
3. Add to cart and checkout through our secure process.
4. Wait for shipping. Most complete uppers ship fast since they don’t require an FFL transfer in most areas (check your local laws to confirm).
5. Install your upper using the steps above once it arrives.