300 AAC Blackout Complete Upper Assembly
High-quality and precisely designed, built, tuned, and tested by the professionals at Alexander Arms® using only the best components we can manufacture


- Picatinny flat-top railed receiver
- Carbine-length gas system
- G10 composite carbine-length handguard
- Picatinny railed gas block
- Military-style trigger
- 16-inch, tightly-dimensioned, 416 stainless steel, 1:8 twist, fluted barrel
- Muzzle threading is 5/8-24 TPI RH
- Direct impingement operating system
Upper receiver features extended feed ramps
- Stock extension tubes and carrier gas keys are properly staked
- This weapon will fire both supersonic and subsonic ammunition
- Weight of upper is 4.15 pounds

This unit is 100% complete and is compatible with any standard-specification lower receiver (no modifications required).

All uppers and rifles are built to order and have an estimated lead time of 4-6 weeks.
Charging Handle Upgrade - Please select this option if you would like to upgrade to the Raptor Ambidextrous charging handle.
Muzzle Upgrades - Please select a muzzle upgrade
Handguard Upgrade - Please select a handguard upgrade. For additional details, you may click the name of each upgrade option.
Camo Upgrades - Select a camo or cerakote upgrade. Requires a non-refundable deposit of the camo upgrade price once the order enters production. Camo is applied to handguard and receiver only. Hydrodipped patterns cannot be combined with Manticore Arms Transformer Rail. Cerakote options (solid colors) can be applied to any handguard upgrade available.
Base Price: $755.21
Selected Options: $0.00
Total Price: $755.21
Fast Shipping

All Alexander Arms® upper receiver assemblies are fully-complete, function-tested, and ready to fire.

This product features a flash hider that is prohibited in states such as New York, New Jersey, and Connecticut. At this time, no upgrade options or alternate muzzle devices are available. The standard, high-capacity magazines included with the rifle are prohibited in states that have high-capacity magazine restrictions. Alternate magazines are not available at this time. Orders placed from any of these states will be shipped without the complimentary magazine.

Don't forget your accessories and ammunition! - We have quality magazines, ammunition, and handguard accessories available for this rifle. Be sure to order these now to avoid additional shipping costs and delays! MK10 rail sections and Manticore Arms panels are sold separately.
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