CM15 300BLK 10.5″ 1:5 Twist Upper with Options

CM15 10.5″ 1:5 Twist Upper with Options

10.5” 1:5 Twist Upper with Options

• CM 6061 lightweight billet aluminum receiver
  • Reliefs featured throughout the receiver
  • Picatinny rail milled channel for a sleek/light weight option
• CM 6061 9.5″ MLOK handguard
  • QD Sockets at 3 and 9 o’clock
  • Full Picatinny top rail
• Choice of Suppressor Host Muzzle Device or Thread Protector
• CM15 Low Mass Bolt Carrier Group
  • 9310 Hardened Steel Bolt
  • 17-4 Stainless Steel Firing Pin
  • 8620 Carrier and Key
  • MPI Tested
  • Hardened Extractor S7 Steel
• CM15 Warhammer Ambidextrous Charging Handle – in collaboration with Breek Arms
• Superlative Arms Adjustable Gas Block
• CM Melonite Gas Tube
• CM15 300 BLK 10.5″ Barrel
  • CrMV
  • Medium Profile
  • Nitride
  • 1:5 Twist
  • Pistol Gas
  • .750 Gas Journal
  • 5/8×24 threaded muzzle

CM15 300BLK 10.5″ 1:5 Twist Upper: The Ultimate Subsonic Specialist

Unlock the true potential of the .300 Blackout platform with the CM15 10.5″ Upper, featuring a high-performance 1:5 twist rate. While standard barrels often struggle to stabilize heavy projectiles, our 1:5 ultra-fast twist is specifically engineered to spin-stabilize heavy subsonic rounds, ensuring surgical accuracy and devastating terminal expansion even at lower velocities.

Optimized for Suppression

The 10.5-inch barrel length is the “sweet spot” for the .300 BLK cartridge, offering a full powder burn while keeping the overall profile compact. This makes it the premier choice for a suppressed “honey badger” style build. The pistol-length gas system ensures reliable cycling with both super and subsonic ammunition, providing the versatility needed for home defense or tactical training.

Built Your Way

With our customizable options, you can fine-tune this upper to your exact requirements. Select from a variety of M-LOK handguards for light and laser integration, or upgrade the Bolt Carrier Group (BCG) for maximum durability under suppressed fire.

Key Features:

• 1:5 Twist Rate: Optimized for heavy 200gr+ subsonic projectiles.

• 10.5” Barrel: The ideal balance of compact handling and ballistic efficiency.

• Versatile Performance: Flawless transition between suppressed and unsuppressed use.

The CM15 300BLK Upper is a purpose-built solution for shooters who refuse to compromise on stealth and stability.