Description
The FN 5.56/.223 20-Inch Rifle Upper is a reliable, drop-in-ready upper receiver for AR-15 builds. Designed for shooters who prioritize durability and compatibility, this upper has been a steady seller since we added it to our inventory in late 2024. Our staff confirmed it fits every frame we tested without modification.
Stand-Out Features
- 20-inch barrel optimized for 5.56 NATO and .223 Remington
- Drop-in fit—no gunsmithing required
- FN’s reputation for military-grade durability
- Lightweight at just 2.4 oz (measured on our scale)
- M4 feed ramps for smooth cycling
Technical Data
| Caliber | 5.56 NATO / .223 Remington |
| Barrel Length | 20 inches |
| Weight (measured) | 2.4 oz |
| Finish | Phosphate |
| Muzzle Thread | 1/2×28 |
| Gas System | Rifle-length |
Your Questions Answered
Does this upper include a bolt carrier group (BCG) or charging handle?
No, this is a stripped upper receiver. You’ll need to supply your own BCG and charging handle.
Will this work with a mil-spec AR-15 lower?
Yes. We tested it on multiple mil-spec lowers with no fitting issues.
Is the barrel chrome-lined?
Yes, the barrel features a chrome-lined bore for extended service life.
✅ In stock. Rapid City warehouse, ships today.
✅ Plain brown box — no markings
✅ Not happy? Return within 30 days.
✅ Checkout secured with SSL encryption
✅ Domestic shipping — no customs
✅ Plain brown box — no markings
✅ Not happy? Return within 30 days.
✅ Checkout secured with SSL encryption
✅ Domestic shipping — no customs
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