The Daniel Defense M4A1 FSP upper receiver is purpose-built for shooters who want a proven platform inspired by the USSOCOM SOPMOD Block II—without the budget-breaking price tag. This 14.5" 5.56 NATO complete upper in Flat Dark Earth combines mil-spec construction with the reliability that professionals demand. Whether you're assembling a precision rifle, upgrading an existing build, or matching the setup you've trained on, this upper delivers the features and accuracy you expect from Daniel Defense.
The heart of this upper is a cold hammer-forged, chrome-lined barrel with a 1:7 twist rate that handles everything from match ammo to steel-cased training rounds. The M4 profile keeps weight down without sacrificing stiffness, while the mil-spec phosphate finish protects against corrosion in any weather. All the fundamentals are here: mil-spec feed ramps, proper gas tube sizing (carbine length, direct impingement), and a pinned-and-welded Surefire SF3P flash hider that's also rated as a suppressor adapter for future quieter builds.
The handguard deserves its own mention. The Daniel Defense RIS II is a quad-rail interface system that's tough enough for duty use but refined enough for precision work. The M16-profile bolt carrier group is chrome-lined, properly staked, and tested to military specifications—meaning zero surprise malfunctions when you need reliability. The A1.5 fixed rear sight and F-marked front sight base let you run iron sights out of the box, and the included QD swivel attachment point handles a sling securely.
Drop this upper on a mil-spec lower and you're ready to shoot. No surprises, no compromise, no wasted features.
| Caliber | 5.56 NATO |
| Barrel Length | 14.5" |
| Barrel Profile | M4 |
| Barrel Material | Chrome Moly Vanadium Steel, cold hammer-forged, chrome-lined |
| Twist Rate | 1:7 |
| Upper Receiver Material | 7075-T6 Aluminum, mil-spec with M4 feed ramps |
| Handguard System | Daniel Defense RIS II quad-rail, 6061-T6 aluminum, Type III hard coat anodize |
| Handguard Finish | Flat Dark Earth |
| Gas System | Direct impingement, carbine length |
| Muzzle Device | Surefire SF3P flash hider / suppressor adapter, pinned and welded |
| Muzzle Device Finish | Black Ionbond DLC coated |
| Bolt Carrier Group | M16 profile, mil-spec MP tested, chrome-lined, properly staked gas key |
| Front Sight | Mil-spec F-marked front sight base |
| Rear Sight | A1.5 fixed, 6061-T6 aluminum, Type III hard coat anodize |
| Accessories Included | QD swivel attachment point, QD swivel |
Yes, as long as your lower is mil-spec and chambered in 5.56 NATO. This is a standard AR-15 interface upper receiver, so it pairs with any mil-spec lower without issue.
The SF3P is both a flash hider and a suppressor adapter, so yes—it's designed to accept compatible Surefire suppressors. The device is pinned and welded to the 14.5" barrel, so it's a permanent installation.
This upper comes complete with the barrel, bolt carrier group, handguard, sights, muzzle device, and a QD swivel. You'll need to add a mil-spec lower receiver, charging handle, and furniture (stock, grip) to finish the rifle.
The A1.5 fixed rear sight is not adjustable. It's a mil-spec design proven for reliability and comes pre-assembled on the upper.
Daniel Defense
Daniel Defense
