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Questions & Answers
Is the barrel hammer forged Expert Answer

The Mitchell Defense DOC AR-15 .300 BLK 10.3in Upper Receiver does not feature a cold hammer forged barrel. It features a 10.3" Chrome Moly Vanadium barrel with a QPQ (nitride) finish.

by Ethan, Gear Expert, July 14, 2026
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6 Models Available
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Product Info for Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver

The Mitchell Defense DOC 10.3in .300 Blackout Upper Receiver is optimized for suppressed and unsuppressed reliability with both subsonic and supersonic ammunition. The billet 7075-T6 upper includes a thermal-fit barrel seat that enhances barrel alignment and accuracy. The 10.3in barrel offers balanced rigidity and reliable ballistic performance. A standard adjustable gas block allows fine-tuning of cycling behavior to match suppressor setups or load variations. The ArmorLube Carbon Cutter BCG with Carpenter 158 HP/MPI bolt improves reliability and reduces fouling. A free-float M-LOK handguard provides versatile accessory mounting. Finished in E-Series Cerakote.image

Specifications for Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver:

Manufacturer: Mitchell Defense
Caliber: .300 AAC Blackout
Overall Length: 21 in
Barrel Length: 10.3 in
Barrel Profile: Standard
Gas System Length: Carbine Length
Barrel Twist Rate: 1-7
Firearms Threads Per Inch: Non Threaded
Muzzle Device: A2 Flash Hider
Finish: Nitride
Gun Model: AR-15
Fabric/Material: 4150 CrMoV
Gun Make: AR Platform
Bolt Carrier Group Included: MIL-SPEC
Charging Handle Included: MIL-SPEC
Country of Origin: USA

Features of Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver

  • Adjustable gas block enables precise tuning for ammunition and suppressors
  • Thermal-fit billet upper enhances stability and accuracy
  • ArmorLube Carbon Cutter BCG with C158 HP/MPI bolt ensures dependable cycling
  • M-LOK handguard provides lightweight modularity

Package Contents:

  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver

Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver Orderable Models

List of Orderable Models

  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Black Finish, Quad Rail Handguard, 421122 , MPN: 421122 , UPC: 850073456330 , Code: 6PS-UFH-VGB17-421122
  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Jungle Green Finish, M-LOK Free-Float Handguard, 421321 , MPN: 421321 , UPC: 850073456361 , Code: 6PS-UFH-VGB17-421321
  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Jungle Green Finish, Quad Rail Handguard, 421322 , MPN: 421322 , UPC: 850073456378 , Code: 6PS-UFH-VGB17-421322
  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Black Finish, M-LOK Free-Float Handguard, 421121 , MPN: 421121 , UPC: 850073456323 , Code: 6PS-UFH-VGB17-421121
  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Flat Dark Earth Finish, M-LOK Free-Float Handguard, 421221 , MPN: 421221 , UPC: 850073456347 , Code: 6PS-UFH-VGB17-421221
  • Mitchell Defense The DOC AR-15 .300 BLK 10.3in Upper Receiver, Chrome-Moly Barrel, Flat Dark Earth Finish, Quad Rail Handguard, 421222 , MPN: 421222 , UPC: 850073456354 , Code: 6PS-UFH-VGB17-421222
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Last updated 2026-10-01 UTC.