5.56 NATO / .223 Wylde Assembled Complete Upper
From: $599.00
Your 5.56/.223 Wylde Upper. Your Way.
Most AR-15 complete uppers come with parts you’re just going to swap out as soon as you open the box. At Grendel Hunter, we don’t believe in making you pay for parts you’re just going to throw in a spare parts bin. Have it built your way from the beginning and skip the box of leftover parts.
How it Works
Our Custom Upper Builder lets you spec out your upper exactly how you want it from the start. We offer numerous options for barrels, handguards, BCG’s etc. The base price is for a complete, fully assembled upper. If you want to upgrade a component—like switching a mil-spec charging handle for an ambidextrous one—just select your preference and the total at the bottom of the page will update automatically.
A Note on BCG's
The base price includes a Bolt Carrier Group. However, if you already have a BCG for this caliber, we aren’t going to force you to buy another one. Selecting “None” for that component will give you a $100 discount at checkout.
(Please Note: This $100 discount is applied in the cart and will not be reflected in the “Grand Total” at the bottom of this builder page.)
Product Details
At the bottom of this page we’ve included in-depth descriptions of various components as well videos and FAQ’s.
Save with an Optics Bundle
SAVE! Get up to $250 off any Complete Upper with the purchase of an Optic
5.56 NATO & .223 Wylde Barrels
Your barrel is the heart of the system. We offer a 16″ M4 contour 5.56 NATO barrel as well as 16″ & 18″ lengths .223 Wylde barrels in a Medium Contour so you can find the perfect balance between velocity and portability for your application.
Material: 416R Stainless Steel for accuracy and durability. (M4 barrel is 4140 CMV)
Finishes: Choose between Uncoated Stainless and Black Cerakote finish for the .223 Wylde. The M4 barrel is a traditional Mag-phos.
Fluting: Available in a Non-Fluted, classic profile or with Straight Flutes for weight savings.
Specifications
- Liberty Barrels® made by Satern®
- 5.56 NATO & .223 Wylde
- 4140 CMV & 416R Stainless Steel
- M4 & Medium Contour
- 1-8 Twist 5R Rifling (M4 is 1-7 Twist 6 Groove)
- Mid Length Gas (M4 is Carbine)
- 1/2-28 Threads
- .750 Gas Block Journal
Grendel Hunter AR-15 Billet Upper Receivers
Forget standard, mass-produced mil-spec forgings. We designed our Grendel Hunter Billet uppers to move beyond the “basic” look of a standard AR. Billet allows us the design freedom to create sharper lines and a more modern aesthetic that you just can’t get from a forging.
We didn’t just design an upper; we designed a system. Our uppers and handguards are engineered to match up in an almost monolithic way, creating a seamless, integrated look.
Slick Side: For the minimalist—no forward assist, shell deflector, or dust cover.
Traditional: Includes all standard features for those who want a classic style upper.
Premium Finishing: Available in Black Hardcoat Anodized, Magpul FDE Cerakote, and Magpul OD Green Cerakote. Note: All Cerakoted uppers are anodized on the interior for maximum durability and smooth cycling.
Specifications
- 6061 T-6 (Slick Side Upper) or 7075 T-6 Aluminum (Traditional Upper)
- M4 Feed ramps
- .250 takedown pin holes
- Forward Assist with threaded roll pin (Traditional Upper)
- Dust Cover (Traditional Upper)
Grendel Hunter AR-15 Handguards: Form & Function
Every Grendel Hunter handguard is designed to integrate seamlessly with our billet uppers, creating a near-monolithic look and a rock-solid mounting platform. While they share the same rugged DNA, each version has a unique style.
Built-In Standards across all models:
Material: Lightweight, high-strength 6061-T6 Aluminum.
Rock-Solid Lockup: A heavy-duty Steel Barrel Nut and Steel Retention System ensure your rail doesn’t shift, even with heavy use.
Anti-Rotation Tabs: Integrated tabs prevent the rail from twisting under torque.
Slim Profile: A 1.3″ inside diameter provides a modern, ergonomic “C-clamp” grip and a sleek look.
- Premium Finishing: Available in Black Hardcoat Anodized, Magpul FDE Cerakote, and Magpul OD Green Cerakote
Which Version is Right for Your Build?
V1:
Front Profile: Aggressive Slant-Cut
Top Rail: Competition Style (Rails at front and back only)
M-LOK Slots: Sides and Bottom
Weight: Our Lightest Option
The V1 is our lightest handguard. By utilizing a competition-style top rail and a sleek slant-cut front, we’ve shed every unnecessary ounce without sacrificing mounting space.
V2:
Front Profile: Traditional Squared-Off
Top Rail: Competition Style (Rails at front and back only)
M-LOK Slots: Sides and Bottom
Weight: Balanced
If you prefer a more traditional look, the V2 features a squared-off front end. It maintains the competition-style top rail for weight savings.
V3:
Front Profile: Aggressive Slant-Cut
Top Rail: Full Picatinny (Continuous top rail)
M-LOK Slots: Full 360° (All sides)
Weight: Built for utility, but our heaviest option
The V3 is our most capable rail. It features a full-length Picatinny top rail and M-LOK slots surrounding the entire circumference. This is the go-to choice for hunters running thermal clip-ons, IR illuminators, or side-mounted accessories.
The Grendel Hunter BCG: Precision-Tuned Reliability
Headspace Check: We perform a manual headspace check for every upper using the specific barrel and bolt you’ve selected.
Optimized Extractor Tension: Excessive tension is a leading cause of malfunctions and extractor failure. We are meticulous about our extractor tension being at the “sweet spot”—ensuring reliable cycling without putting unnecessary stress on the steel.
Built to Last: Our bolts are machined from 9310 Steel, shot-peened for fatigue resistance, and Magnetic Particle Inspected (MPI).
BCG Finish Specifications
Black Nitride
Surface Hardness: ~740 HV (Vickers)
The Process: A salt-bath thermo-chemical treatment that hardens the steel.
The Benefit: Far more durable and smoother than original Mil-Spec magnesium phosphate with excellent corrosion resistance.
BCG Technical Specifications:
Carrier: M16 Auto Profile (8620 Steel) for smooth cycling and increased mass.
Gas Key: 4130 Steel with properly staked Grade 8 fasteners.
Bolt: 5.56 NATO
Small Parts: 4140 Steel Cam Pin and Hard Chrome Firing Pin.
Grendel Hunter Gas Blocks
We exclusively use adjustable blocks in our uppers. With the explosion in popularity that suppressors have enjoyed in recent years, it just makes sense to have the ability to tune the gas. There are two models to choose from.
Note: Every upper is test-fired and shipped pre-set for reliable unsuppressed firing.
GH .750 Adjustable (Set & Forget)
Best For: Those who don’t plan to suppress or shooters who will suppress and want to tune their gas once and leave it. Generally requires handguard removal for adjustment since cutouts in handguards don’t always align with the adjustment screw. Handguard removal is as simple as removing two hex bolts, but it is an extra step.
Design: Side-access adjustment (1/16” Hex) with a front-facing locking screw.
Material: 4140 Steel with a Black Nitride finish.
GH .750 Click Adjustable (Premium)
Best For: Those who suppress or who like to really fine tune their rifles.
Design: Ball-detent system with 22 audible clicks of adjustment across the gas port and zero-shutoff.
Ease of Use: Front-access adjustment screw (1/8″ Hex) allows for tuning without removing the handguard.
Performance: Eliminates the “violent” over-gassed cycle common with suppressors, reducing carrier speed and heat.
Materials: 4140 PHT or 303 Stainless Steel.
Finishes: Black Nitride, Stainless, or Bead Blasted Stainless.
Will my upper come assembled and test fired?
Yes. You choose the components above and we assemble and test fire with those parts.
Will my upper receive a headspace check?
Yes. For every upper we build, we take the specific barrel and bolt the customer has selected and perform a headspace check prior to assembly.
What is the lead time on an upper?
We ship the same or next business day. Since our website has a live inventory and we only sell things that actually exist on our shelves, we do not have lead times.
If a specific component I want is out of stock, can I place the order anyway?
Unfortunately, we do not accept backorders. It’s Grendel Hunter’s policy to only take a customer’s money for things that exist.
If a specific component is out of stock, you can go to that item’s individual product page and join the “Back in Stock” email notification list.
Kevin –
Easy to build
Robert Lee –
Lots of great choices 👍
Derek Pound (verified owner) –
I’m not much of a review person but my AR build came out so far above expectation I felt that I needed to chime in. I had been looking all over the world wide web for an upper receiver to pair with a couple of lowers that I have had sitting around, but no matter how hard I looked I couldn’t find one that was exactly what I was looking for. Whether it was handguard length, the barrel, the compensator, or any other detail, nothing was quite right. That is until I found Grendel Hunter. The ability to mix and match each of the components to end up with a product that I wouldn’t have made differently if i was given free reign in a Optics Planet warehouse, was incredible. I included a Velocity 3lb trigger in that order and then came back to get a new mil-spec buffer tube with the Stealth 4.7oz recoil spring kit. I had been to the range before installing the recoil spring system and was already insanely impressed but once I changed out the spring and buffer tube I could have died a happy man. The gas system needed 0 adjustment to cycle perfectly and all said and done, I can say without hesitation that I have never shot a more stable, accurate, or faster firing semi-auto AR in my life. If you don’t want to take my opinion at face value the 4 other members at my club that squeezed off a mag or two said the exact same thing as well. Between the ability to completely customize every option of your build, the incredible esthetic, how well they function, and the fact that they assembled it and had it shipped within 24 hours of placing my order, I am all in on Grendel Hunter for my next 6.5 Grendel build.