The Battle Arms Development WORKHORSE Complete Upper (BAD part no. WH-UR10.5B-Y-15C) builds a forged 7075-T6 aluminum receiver and matching free-float M-LOK handguard around a 10.5-inch, 4150 chrome-moly barrel chambered in 5.56 NATO/.223 Remington. M-LOK slots run along the 3, 6, and 9 o’clock positions of the handguard, and a full-length Picatinny rail tops the assembly with Battle Arms Development’s signature notch cut matching the receiver. A 9310 steel bolt and 8620 black-nitride carrier are individually head-spaced to the barrel for dependable function and simple field cleaning. This upper ships without a lower receiver, so it’s intended for a pistol-length build or a properly registered short-barreled configuration rather than a standard 16-inch-minimum rifle.

Key Specifications

• Chambered in 5.56 NATO/.223 Remington.
• Barrel cut to 10.5 inches.
• Receiver forged from 7075-T6 aircraft-grade aluminum.
• Free-float handguard with M-LOK slots at 3, 6, and 9 o’clock.
• Full-length Picatinny top rail with a signature notch matching the receiver.
• Barrel machined from 4150 chrome-moly steel.
• Barrel finished in black nitride.
• Individually head-spaced bolt and barrel pairing.
• Matched with a 9310 steel bolt.
• 8620 steel carrier with a black nitride finish for easy cleaning.

Frequently Asked Questions

Does this include a lower receiver? No, it’s sold as a complete upper only; you’ll need your own compatible lower to build a complete rifle or pistol.

Does a 10.5-inch upper need to go on a registered short-barreled rifle? Sold alone, this is an ordinary Title I upper with no lower attached. Federal short-barreled-rifle rules only apply once it’s assembled onto a complete rifle with a shoulder stock; building it as a pistol with an arm brace, or registering it as an SBR through your dealer, are both legal paths. Confirm your configuration with your local FFL before assembly.

What’s included with the barrel? A matched 9310 steel bolt and 8620 black-nitride carrier, individually head-spaced to that specific barrel for reliable function.

Buy the Battle Arms Development WORKHORSE Complete Upper

Order this Battle Arms Development upper from our AR15 uppers selection to build a rugged, reliable 5.56 platform. Contact our Lubbock, Texas gun shop with any configuration questions before it’s ready to ship.