When it comes down to it, many LE officers who have to purchase their own equipment must look for top-noch performance at a reasonable price—not an easy combination. Recently, a new option has entered the market. Huldra Arms came about through the efforts of Mills Fleet Farm, a leading sporting goods retailer in the Midwest. Looking to enter the AR market and develop a line of gas piston-operated rifles, and after a tremendous amount of research and development, Mills Fleet Farm was convinced of the impressive characteristics of quality and performance of the Adams Arms AR piston operating system. The result was the Huldra line of ARs, a joint effort between Adams Arms and Mills Fleet Farm (which is the sole retailer for these rifles).
Huldra Arms is currently offering four ARs. The test sample provided was the Mark IV 5.56 Carbine. In outward appearance the Mark IV Carbine resembles an M4 Carbine. It has the 16-inch barrel, collapsible buttstock, short oval handguard and flattop upper receiver common to that design. What it does not have is the fixed front sight. Even though the rifle will accept mil-spec parts, on the inside it is very different than your common M4-style AR.
The main difference is the piston system, which uses the same gas port as a conventional AR to work the action, but with the Huldra, the gases that pass through the gas port are not directed back to the upper receiver and bolt group through a tube. Instead, they are used to drive a piston that has a small sleeve that fits over a rod at the rear of the gas block. The result is that all the gases are expelled from the rifle at the gas block and little to no gas or carbon fouling enters the action.
According to Huldra Arms, its AR functions and feels like a conventional AR but runs cooler, cleaner and more reliably. Piston-driven ARs are not new—other manufacturers offer them and I have tested several. With the exception of the Huldra, I could feel a difference in the way the rifles recoiled. I’m not saying this was a bad thing, just that it felt different. To me, the Huldra felt like any other standard gas impingement-driven AR.
Another difference you will find with the Huldra is a bolt spring. Behind the bolt and inside the bolt carrier there is a small spring that surrounds the protrusion on the end of the bolt. This spring keeps forward pressure on the bolt at all times. Service members will remember that during training on the maintenance of the M16, they were told to push the bolt to the rear in the bolt carrier, and if it did not rotate and slide forward when they slung the bolt carrier outward, the bolt was not clean. With the Huldra bolt and bolt carrier, you cannot do this because of the continuous pressure exerted on the bolt by the bolt spring. According to Huldra Arms, the bolt spring eliminates cam pin wear.
Because of this spring, the bolt assembly is a bit different as compared to a standard gas impingement-driven AR. When inserting the bolt key, you must hold slight pressure on the bolt to line up the bolt key for insertion. You simply cannot just drop the bolt key into the bolt carrier and bolt. I did find that the firing pin retaining pin on the test rifle was very difficult to remove. It was so hard to reinstall that I buggered it up in the process. I had to borrow a pin from another AR to complete the range testing.