Huldra Mark IV 5.56 Carbine.

Barrel Twist: 1:7 Right Hand - M4 Feed Ramps. Barrel Profile: M4 Contour. Barrel Coating: Melonite. Barrel Lining: Melonite. Barrel Material CrMoV 4150. Upper Receiver: Dry Film Lubed - T Marked. Stock: Mil-Spec 6 Position Tactical Butt Stock. Grip: A2. Fore Arm: M4 Hand Guards. Flash Hider: A2 Flash Hider. 100 Meter Accuracy: 1 MOA. The Huldra Mark IV series of rifles is manufactured for Mills Fleet Farm by Adams Arms. Centerpiece of Huldra Mark IV series of rifles is Adams Arms proprietary piston system. The gas block is a Picatinny style gas block and sits at the same height as the upper receiver. The gas block is set up with 3 different gas setting that are easily adjusted by pressing down the detent pin and rotating the gas plug either clockwise or counter-clockwise. The 12 o’clock position is the full or open position and should be used with normal fire. The 1 o’clock position is the low or suppressed position and is best used with a suppressor on the firearm. The last 3 o’clock position is the off position and allows your AR to fire without cycling the action. Huldra Mark IV 5.56 rifles and uppers are chambered using 5.56 chambers allowing you to shoot both 5.56 ammunition, as well as the lower pressured .233 with no problems. Huldra's Adams Arms Piston System uses the same gas port on the barrel to work the action of our inverted piston. Instead of directing the gases into the receiver, they go into a gas plug and drive rod sleeve. The gases are contained inside the drive rod sleeve and push the bolt carrier rearward using the gas pressure to cycle action. Once the action is cycled the remaining gases are pushed out of the front of the gas block, purging the system and keeping the gases out of the face of the user and the receiver. The end result is a firearm that functions and feels like an AR15 / M16 but burns cooler, cleaner, and is more reliable. The Huldra Mark IV has gone further than just a patented revolutionary operating system. The gas piston system and block are Melonited and the bolt carrier is ion bonded. All of the Piston System parts that operate this rifle come with a lifetime warranty. The Huldra melonited corrosive resistant CrMoV (Chrome-Moly-Vanadium) 4150 barrels provides excellent coating uniformity and no tolerance build up in the barrel to create deviation. Melonited barrels have higher lubricity, last longer and are just plain tougher than chrome lining. The barrel chambers are speed polished reducing resistance on the cartridge entering and exiting the chamber. The upper and lower receivers are machined from high quality mil-spec 7075-T6 aluminum forgings, with critical tooling dimensions held within ±.001" and Type III Hardcoat finished. The mil-spec buffer tube is precision machined from 7075-T6 aluminum as well. The magwell front features recessed chevrons for improved control.