NBS 8.5" .300 BLK Pistol M-LOK Upper Assembly

A quality upper assembly without cutting corners. This means starting with a top tier billet upper receiver, using a steel gas block as opposed to aluminum, and Dirty Bird M-LOK handguards. We use Permatex 242 on key components while using mil-spec AEROSHELL 33MS Anti-Seize grease on the properly torqued barrel nut and muzzle device. 300BLK is a great round for home defense and hunting. We wanted to maximize this by adding a flash can to direct all flash forward and make follow up shots easier. We wanted to reduce weight, so we included the Dirty Bird Gen 2 Handguard, which features a shaved top rail and M-LOK mounting slots on every side of the handguard. The Dirty Bird handguards have one of the most secure locking systems in the patent-pending ASAL locking system to ensure your handguard will not cant or have unwanted rotation. This also means taking the time to ensure that the upper will function reliably. When you are looking to build your next pistol upper, look no further than the new NBS 8.5″ 300BLK Pistol Upper.

Bottom line is this: you hear all the time about guys buying a budget upper and it not lasting or having to send it back because of some hardware defect or other issue caused by a careless assembly process. That is why we use top tier components and assemble each unit to the highest standard of quality. We want your upper to function flawlessly out of the box. In fact, we guarantee it will.

Buy with confidence, this upper is backed by our 30 day satisfaction guarantee. Buy it, run it, abuse it, and if you aren’t satisfied you can send it back for a full refund.

Lifetime Warranty

Guaranteed Sub-MOA performance with match grade ammo and proper shooting technique

Made in the USA

NBS Slick Side Billet Upper Receiver

• M4 Feedramps
• Compatible with mil-spec forged lower receivers and most billet lower receivers
• .250 takedown / pivot pin holes
• No forward assist
• Designed to be used with or without a port door / dust cover (will need to remove e-clip from dust cover pin before assembly)
• Weight: 7.1oz

Dirty Bird AR-15 SMRS Handguard – Slim M-LOK Rail System Gen 2

Tough

• Machined from aircraft grade 6061-T6 aluminum extrusions.
• Type 3 hard anodizing or Cerakote™ sprayed at 1 mil thickness per spec.

Versatile

• M-LOK attachment slots on all sides, including the shaved portion of the top rail.
• 1913 Picatinny top rail with shaved and beveled center section.
• Snag free design with smooth, uniform octagonal surface ideal for accessory attachment or application of specialty coatings or patterns.

Practical

• This version features the patent pending anti-slip / anti-lift attachment method (ASAL^TM) for an easy, timing-free installation that provides an extremely rigid and secure attachment. Read below for more technical details about this impressive new attachment method.
• Compatible with most known low profile gas blocks.

Straight Forward Installation

• Using only a 1-3/16 Crow’s Foot wrench and 5/32″ Allen key
• Barrel nut does not requiring timing with the gas tube. No shims required.

The end result is a great looking, zero compromise handguard suitable for a wide variety of builds.

Interior Diameter

1.35″” ID

1.7″” Maximum Vertical ID (for considering vertical height of gas blocks)