DEMO Angstadt Arms MDP-9 6in Complete Roller Delay Upper Receiver Assembly - Surpressor Ready Black 9mm. With a proven roller-delayed action and AR-15 platform compatibility the MDP-9 Complete uppers delivers the ideal weapon system for both professionals and prepared citizens alike. The MDP-9 is chambered in 9mm and compatible with most Mil-Spec AR-9 lower receivers. Specifications for Angstadt Arms MDP-9 6in Complete Roller Delay Upper Receiver Assembly: Manufacturer: Angstadt Arms Caliber: 9mm Luger Overall Length: 14 in Barrel Length: 5.85 in Muzzle Device: Flash Hider Finish: Matte Color: Black Weight: 3.7 lb Magazine Included: No Mount Type: Picatinny Attachment Type: Picatinny Features of Angstadt Arms MDP-9 6in Complete Roller Delay Upper Receiver Assembly Proven reliability - Operates on a patent pending roller-delayed action Extremely lightweight - less than 3.7lbs Ultra-compact - Just 14" 5.85" MP5 profile barrel with 3-lug Includes a 1913 picatinny end plate that accepts a wide variety of stabilizing braces and rifle stocks Non-reciprocating forward charging handle that can be swapped from left to right side Works with most last round bolt hold open features utilizing a Mil-spec bolt catch Package Contents: Angstadt Arms MDP-9 6in Complete Roller Delay Upper Receiver Assembly Angstadt Arms AAUMDP0906: MDP-9 6in Complete Roller Delay Upper Receiver Assembly - Surpressor Ready Black 9mm