Your basket is empty.

Basket

Help and contact

Free standard delivery over £199

100-day return policy

Sale

Over 300,000 customers - we say thank you!

4.93/5 "Very good" (1400+ reviews)

40,000+ products for hunting and shooting sports

.300 Blackout complete upper receiver with a 10.5" barrel, M-LOK handguard, and nitride BCG for compact AR builds, ideal for pistols and SBRs.

-11 %

ONE HORSE 300BLK 10.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

850078799326 430118802

Filters:

Variations

Filters:

Variations:

-11 %

.300 Blackout complete upper receiver with a 10.5" barrel, M-LOK handguard, and nitride BCG for compact AR builds, ideal for pistols and SBRs.

300BLK 10.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

409.9 GBP 6 £409.90 * £459.90

In stock

Cartridge: 300 AAC Blackout Color: Black Contour: Medium Finish: Matte Length: 10.5'' Make: AR-15 Muzzle: 5/8-24 Style: Complete Twist: 1-7 Product no.: 430118802

In stock

409.9 GBP 6 £409.90 * £459.90

-9 %

.300 Blackout complete upper receiver with M-LOK handguard, nitride BCG, and compact design for reliable performance in AR pistols and SBRs.

300BLK 7.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

399.9 GBP 7 £399.90 * £439.90

In stock

Cartridge: 300 AAC Blackout Color: Black Contour: Medium Finish: Matte Length: 7.5'' Make: AR-15 Muzzle: 5/8-24 Style: Complete Twist: 1-7 Product no.: 430118804

In stock

399.9 GBP 7 £399.90 * £439.90

399.9 409.9 2 GBP

-11 %

MSRP £459.90

409.9 GBP £409.90

Prices inclusive of duty & VAT.

Product no.: 430118802

Mfr. No.: OH-CU05

850078799326 ONE HORSE 300BLK COMPLETE UPPER RECEIVER W/MEDIUM PISTOL BBL FOR AR-15 Build a compact, hard-hitting AR platform with this .300 Blackout complete upper receiver, designed for reliability, maneuverability, and close-quarters performance. Fully assembled and ready to install, this upper is an ideal solution for pistol or SBR configurations where compact size matters. At the core is a 300 Blackout barrel, optimized for strong performance in shorter barrel lengths while maintaining excellent energy and versatility with a wide range of bullet weights. The compact design makes it well-suited for suppressed or unsuppressed setups. The M-LOK free-float handguard provides a slim, lightweight profile while enhancing barrel stability for improved accuracy. With multiple attachment points, it offers flexibility for adding lights, grips, or other essential accessories. A nitride bolt carrier group ensures smooth, reliable cycling with enhanced durability and corrosion resistance, while the included charging handle completes the package for true plug-and-play convenience. Built for compatibility with standard mil-spec AR-15 lowers, this upper is ready to pin on and run right out of the box. FEATURES .300 Blackout Barrel – Compact, powerful performance optimized for short platforms Short-Barrel Configuration – Ideal for AR pistols, SBRs, and suppressed applications M-LOK Free-Float Handguard – Lightweight and modular with improved barrel stability Nitride Bolt Carrier Group – Durable, corrosion-resistant, and low maintenance Compact & Maneuverable – Perfect for confined environments and fast handling Full-Length Picatinny Rail – Ready for optics and accessories Mil-Spec Compatibility – Fits standard AR-15 lower receivers Made in USA – Built with quality materials and dependable craftsmanship WHAT’S INCLUDED Complete upper receiver assembly 7300 Blackout barrel M-LOK free-float handguard Nitride bolt carrier group (BCG) Charging handle Barrel nut and mounting hardware SPECIFICATIONS Caliber: .300 AAC Blackout Gas System: Pistol-Length Rail: Picatinny top rail Compatibility: Mil-Spec AR-15 lowers Country of Origin: USA

In stock 6 pcs. in the USA warehouse

Delivery time approx. 7-14 days.

100-Day Return Policy

No charges until we ship

No charge:
Your credit card will not be charged when you place your order.

No commitments:
You are under no obligation until the goods are shipped. You can cancel your order at any time before shipping - free of charge.

Not until shipping:
Your credit card will only be charged once we ship your order. Not before.

Compact & powerful performance
M-LOK free-float handguard
Nitride bolt carrier group

Wish List Ask question

order by phone

399.9 409.9 2 GBP

Description Specification Customers reviews Accessories

ONE HORSE 300BLK 10.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

-11 %

MSRP £459.90

409.9 GBP £409.90

Prices inclusive of duty & VAT.

Is a 'Call to order' product.

Requires order by phone

Description:

ONE HORSE 300BLK COMPLETE UPPER RECEIVER W/MEDIUM PISTOL BBL FOR AR-15 Build a compact, hard-hitting AR platform with this .300 Blackout complete upper receiver, designed for reliability, maneuverability, and close-quarters performance. Fully assembled and ready to install, this upper is an ideal solution for pistol or SBR configurations where compact size matters. At the core is a 300 Blackout barrel, optimized for strong performance in shorter barrel lengths while maintaining excellent energy and versatility with a wide range of bullet weights. The compact design makes it well-suited for suppressed or unsuppressed setups. The M-LOK free-float handguard provides a slim, lightweight profile while enhancing barrel stability for improved accuracy. With multiple attachment points, it offers flexibility for adding lights, grips, or other essential accessories. A nitride bolt carrier group ensures smooth, reliable cycling with enhanced durability and corrosion resistance, while the included charging handle completes the package for true plug-and-play convenience. Built for compatibility with standard mil-spec AR-15 lowers, this upper is ready to pin on and run right out of the box. FEATURES .300 Blackout Barrel – Compact, powerful performance optimized for short platforms Short-Barrel Configuration – Ideal for AR pistols, SBRs, and suppressed applications M-LOK Free-Float Handguard – Lightweight and modular with improved barrel stability Nitride Bolt Carrier Group – Durable, corrosion-resistant, and low maintenance Compact & Maneuverable – Perfect for confined environments and fast handling Full-Length Picatinny Rail – Ready for optics and accessories Mil-Spec Compatibility – Fits standard AR-15 lower receivers Made in USA – Built with quality materials and dependable craftsmanship WHAT’S INCLUDED Complete upper receiver assembly 7300 Blackout barrel M-LOK free-float handguard Nitride bolt carrier group (BCG) Charging handle Barrel nut and mounting hardware SPECIFICATIONS Caliber: .300 AAC Blackout Gas System: Pistol-Length Rail: Picatinny top rail Compatibility: Mil-Spec AR-15 lowers Country of Origin: USA

Restrictions

This product is only available for sale in United Kingdom

Is a 'Call to order' product.

Attributes

Cartridge:
```
300 AAC Blackout
```
Colour:
```
Black
```
Contour:
```
Medium
```
Finish:
```
Matte
```
Length:
```
10.5''
```
Muzzle:
```
5/8-24
```
Style:
```
Complete
```
Twist:
```
1-7
```
Weapon type:
```
AR-15
```
Delivery weight: 1.814kg
Shipping height: 254mm
Shipping width: 102mm
Shipping length: 152mm
UPC: 850078799326

Item details

Made in USA
US export classification: 0A509.b

Customers reviews

Customer ratings (0)

0 / 5

Variations:

-11 %

300BLK 10.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

409.9 GBP 6 £409.90 * £459.90

In stock

Cartridge: 300 AAC Blackout Color: Black Contour: Medium Finish: Matte Length: 10.5'' Make: AR-15 Muzzle: 5/8-24 Style: Complete Twist: 1-7 Product no.: 430118802

In stock

409.9 GBP 6 £409.90 * £459.90

-9 %

300BLK 7.5" MEDIUM PISTOL BBL COMPLETE UPPER RECEIVER

399.9 GBP 7 £399.90 * £439.90

In stock

Cartridge: 300 AAC Blackout Color: Black Contour: Medium Finish: Matte Length: 7.5'' Make: AR-15 Muzzle: 5/8-24 Style: Complete Twist: 1-7 Product no.: 430118804

In stock

399.9 GBP 7 £399.90 * £439.90

Oops! Something went wrong.

We encountered an error while loading this content. Please refresh the page to continue. If the issue persists, contact our customer support.

Site Navigation

Product Categories

Ordering

Customer Service

Connect

Secure payment methods

Trade Associations

Welcome!

Welcome to Odos!

Your European partner for shooting sports, hunting and legal firearm ownership. We share your passion and offer a huge selection of firearms, parts, accessories, gunsmithing tools, optics and reloading equipment, including many products that are hard to find elsewhere in Europe.

Our mission goes beyond selling products. We want to strengthen legal firearm ownership, remove unnecessary barriers and grow our community.

For Shooters, By Shooters

We're part of the community ourselves. We share your passion and understand what matters to you.

Huge Selection

From everyday replacement parts to rare specialist equipment, you'll find everything you need in one place.

Decades of Experience. A New Name.

Formerly Midway Europe, then Brownells Europe, now Odos. Since the 1990s, we've stood for expertise, experience and a passion for firearms.

Explore our selection and support our mission to strengthen legal firearm ownership in Europe with every purchase.

Odos. Our Way Forward.