Dirty Bird 18 SPR 6mm ARC Stainless Rifle M-LOK Complete Upper

6mm ARC is quickly becoming one of the most versatile rounds for the AR-15. With better ballistic coefficients and velocity than 5.56 and .223 and a flatter shooting experience compared to .308, it's no wonder this cartridge is becoming wildly popular! The Dirty Bird 6mm ARC complete upper is great for anything from hunting medium to large game, hitting targets at a 1000 yards with ease, and everything in between. The 18" 6mm ARC Complete Upper is built with accuracy and maneuverability in mind, which is why we went with the following components: Ballistic Advantage 18 6mm ARC SPR Profile SPR Profile 416R Stainless Steel to maintain the highest level of accuracy 1:7 Twist Rate to stabilize most types of ammunition Dirty Bird AR-15 SMRS Handguard - Slim M-LOK Rail System Gen 3 Tough Machined from aircraft grade 6061-T6 aluminum extrusions. Type 3 hard anodizing or Cerakote(TM) sprayed at 1 mil thickness per spec. Versatile M-LOK attachment slots on all sides Full 1913 picatinny top rail Snag free design with smooth, uniform octagonal surface ideal for accessory attachment or application of specialty coatings or patterns. The Gen 3 Handguard features integral 5 slot 1913 Picatinny Rail sections on the 12, 3, 6, and 9 o' clock positions at the mouth of the handguard Practical This version features the patent pending anti-slip / anti-lift attachment method (ASALTM) 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. Upper Receiver Precision Machined from Top Tier 7075-T6 Aluminum Forgings (forge marks may vary) Not all foged uppers are created equal and we only use the best for our uppers meaning they will be free from excessive pitting, machined to spec and finished with quality (not purple or chalky) hard coat anodizing M4 Feedramps M16 / AR15 6.5 Grendel BCG 8620 M16 style carrier 9310 6.5 Grendel bolt 4140 billet gas key 4140 Cam Pin nitride treated for wear resistance Billet Machined Extractor Firing pin precision machined from 17-4 H-900 Stainless Steel Charging Handle Mil-Spec Style 6061-T6 Billet Aluminum Smooth Operation and Positive Grip under Extreme Conditions Type 3 Class 2 Hard Coat Anodizing Made in the USA Dirty Bird Industries' Limited Lifetime Warranty