The Davidson Defense Stratosphere 18" 6MM ARC AR-15 complete upper build is engineered for those who prioritize precision and reliability in the high-performance 6mm ARC cartridge. Built around an 18-inch 4150 CrMoV barrel with 1:7.5 twist rate, this upper offers optimal stability and accuracy for every shot across diverse 6mm ARC projectile weights. The barrel is finished with a durable nitride treatment and features a government profile with 0.750 gas block size for reliable operation. The rifle-length gas system ensures smooth operation under various conditions with reduced recoil and consistent cycling. The 15-inch freefloat M-Lok handguard in black finish provides a sleek and customizable interface for attaching accessories while maintaining stability during shooting. The upper receiver is constructed from robust 7075-T6 aluminum with anodized finish for extra protection. The complete upper includes a mil-spec AR-15 M4 charging handle and complete bolt carrier group composed of 9310 and 8620 alloy steel with QPQ nitride finish for enhanced durability. This complete upper build is ideal for gunsmiths looking for a reliable, high-performance platform in 6mm ARC.
The 18-inch barrel is constructed from 4150 CrMoV steel with durable nitride treatment, ensuring reliable operation and long-lasting performance in the 6mm ARC chambering. The government profile provides a balanced weight distribution suitable for extended barrels, maintaining structural integrity while managing heat during extended shooting sessions. The nitride treatment enhances surface hardness and provides superior corrosion resistance for consistent performance across varied environmental conditions. The 1:7.5 twist rate offers optimal stability and accuracy for every shot, specifically engineered for 6mm ARC projectile weights from 103-grain bullets for versatile applications to 108-grain match projectiles for precision long-range shooting. This twist rate ensures proper stabilization of the high-BC bullets that make the 6mm ARC cartridge particularly effective for long-range applications. The extended 18-inch length provides enhanced velocity, maximizing the ballistic efficiency of the 6mm ARC cartridge.
The rifle-length gas system with 0.750 gas block size ensures smooth operation under various conditions, providing reduced felt recoil and consistent cycling compared to shorter gas system configurations. The rifle-length configuration contributes to improved shooter comfort and faster follow-up shots during precision shooting sessions, maximizing the benefits of the extended barrel length and efficient 6mm ARC cartridge. This gas system length ensures reliable extraction and ejection while delivering the smooth operation engineered into this platform. The 7075-T6 aluminum upper receiver with anodized finish offers robust construction for extra protection, providing exceptional strength-to-weight ratio and enhanced corrosion resistance for demanding shooting applications.
The included complete bolt carrier group is composed of 9310 and 8620 alloy steel with QPQ nitride finish, providing enhanced durability through superior material selection. The 9310 steel is commonly used for bolt construction due to its superior fatigue resistance, while 8620 alloy steel provides excellent wear characteristics for the carrier body. The QPQ nitride finish (also known as Quench-Polish-Quench or Melonite) provides exceptionally hard, corrosion-resistant surface that reduces friction for smoother operation while supporting reliable long-term performance across thousands of rounds. This premium finish ensures the BCG maintains consistent cycling and extraction performance. The mil-spec AR-15 M4 charging handle provides standard Mil-Spec design for reliable operation and broad compatibility with aftermarket upgrades and accessories.
The 15-inch freefloat M-Lok handguard in black finish provides a sleek and customizable interface for attaching accessories while maintaining stability during shooting. The freefloat design isolates the barrel from external contact, supporting enhanced accuracy potential by eliminating pressure points that can affect barrel harmonics during firing—critically important for precision shooting applications where the 6mm ARC cartridge delivers exceptional accuracy at extended ranges. The extended 15-inch length provides excellent coverage of the 18-inch barrel while offering ample M-Lok mounting space for lights, laser devices, vertical grips, bipods, and other accessories at multiple positions. This sleek, customizable interface allows shooters to configure the platform for long-range precision shooting and competition applications while maintaining the stability and lightweight characteristics that complement the efficient 6mm ARC cartridge.
This complete upper build delivers a reliable, high-performance platform engineered for those who prioritize precision and reliability. The combination of 4150 CrMoV barrel with nitride treatment, smooth-operating rifle-length gas system, premium QPQ nitride BCG, and sleek M-Lok handguard creates a comprehensive solution ideal for gunsmiths seeking optimal stability and accuracy for every shot in the versatile 6mm ARC cartridge. Ready to pair with your preferred lower receiver for immediate use.
Follow safe handling practices and manufacturer instructions for assembly and use. Ensure compliance with all applicable federal, state, and local laws. This upper is chambered in 6mm ARC. Complete upper pairs with lower receiver.
Caliber: 6mm ARC
Barrel Length: 18-inch
Barrel Twist Rate: 1:7.5
Barrel Material: 4150 CrMoV
Barrel Finish: Nitride
Barrel Profile: Government
Gas System Length: Rifle
Gas Block Size: 0.750
Barrel Thread Pitch: 5/8x24
Upper Receiver Material: 7075 T6 Aluminum
Upper Receiver Finish: Anodized
Handguard Style: M-Lok
Handguard Color: Black
Charging Handle: AR-15 M4 Charging Handle Mil-Spec Quality
Bolt Carrier Material: 9310 Alloy Steel (Bolt Head), 8620 Alloy Steel (Body)
Bolt Carrier Finish: Nitride
Bolt Carrier: 6.5 Grendel II QPQ Nitride Complete Bolt Carrier Group
Muzzle Thread Pitch: 5/8x24
Muzzle Device: AR-15/AR-10 .308 5/8x24 TPI GI Birdcage Flash Hider
To view the most up-to-date shipping times Click HERE. To view Warranty, Returns, Terms & Restrictions Click HERE. To view State Restrictions Click HERE.
