.450 Bushmaster Assembled Complete Upper

Ballistics Barrel Upper Receiver Handguard BCG Gas Block FAQ Videos Best .450 Bushmaster Hunting Loads: 100 & 200 Yard Ballistic Test Best .450 Bushmaster Hunting Loads: 100 & 200 Yard Ballistic Test Tested Ammo Muzzle Velocity (fps) Muzzle Energy (ft/lb)   Hornady 250gr FTX | B.C. Read More » .450 Bushmaster BarrelsYour barrel is the heart of the system. We offer 16″ & 18″ lengths 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. Finishes: Choose between Uncoated Stainless, Black Cerakote, or a Bead Blasted Stainless finish. SpecificationsLiberty Barrels® made by Satern®.450 Bushmaster416R Stainless SteelMedium Contour1-20 Twist 6 Groove RiflingMid Length Gas3/4×24 Threads.875 Gas Block Journal Grendel Hunter AR-15 Billet Upper ReceiversForget standard, mass-produced mil-spec forgings. We designed our Grendel Hunter Big Bore 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. 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. Specifications7075 T-6 Aluminum .250 takedown pin holesOversized ejection port for reliable ejection of Big Bore brassSlick Side (No dust cover or forward assist) Grendel Hunter AR-15 Handguards: Form & FunctionEvery 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 CerakoteWhich 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 ReliabilityHeadspace 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). Professional Grade FinishesWe offer three distinct finishes, each offering a significant upgrade over the old Mil-Spec phosphate in terms of lubricity, hardness, and ease of cleaning. BCG Finish SpecificationsBlack 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. Nickel Boron (NiB) Surface Hardness: ~1800 HV (Vickers) The Process: UCT EXO® (High Boron content). The Benefit: An extremely hard, durable finish with a very low friction coefficient. It’s smooth and wipes clean easily. DLC (Diamond-Like Carbon) Surface Hardness: ~2300 HV (Vickers) The Process: Next-level Plasma Enhanced Chemical Vapor Deposition (PECVD) The Benefit: High hardness, Excellent abrasive wear resistance, Low thermal conductivity, Ultra-Low friction level. 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: .450 Bushmaster / .458 SOCOM Small Parts: 4140 Steel Cam Pin and Hard Chrome Firing Pin. Grendel Hunter Gas BlocksWe 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.  Note: Every upper is test-fired and shipped pre-set for reliable unsuppressed firing. GH .875 Click AdjustableBest 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. Finish: Black Nitride 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. {"@context":"https:\/\/schema.org","@type":"FAQPage","mainEntity":[{"@type":"Question","name":"Will my upper come assembled and test fired?","acceptedAnswer":{"@type":"Answer","text":"Yes. You choose the components above and we assemble and test fire with those parts.\u00a0"}},{"@type":"Question","name":"Will my upper receive a headspace check?","acceptedAnswer":{"@type":"Answer","text":"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."}},{"@type":"Question","name":"What is the lead time on an upper?","acceptedAnswer":{"@type":"Answer","text":"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.\u00a0"}},{"@type":"Question","name":"If a specific component I want is out of stock, can I place the order anyway?","acceptedAnswer":{"@type":"Answer","text":"Unfortunately, we do not accept backorders. It’s Grendel Hunter’s policy to only take a customer’s money for things that exist.\u00a0If 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."}}]} Playlist .450 Bushmaster Ballistics Comparison Don’t forget magazines!