Precision/Varmint Rifle Build: Part 4, The Barrel
The true heart of any rifle is the barrel. As explained in Part 2, for a flattop AR platform rifle, the barrel is the most important puzzle piece for accuracy. Since the intended purpose of the gun is to shoot varmints, and maybe a PRS gas gun match here and there, this rifle would benefit from some extra length for added velocity, and profile weight for rigidity. What I have chosen for this build is a Wilson Combat match grade barrel chambered in 5.56 NATO. This barrel features an 18″ length, SPR profile, stainless steel construction, and a 1-8 twist. Wilson Combat is known for its high quality parts, and their barrels are no exception. This barrel was chosen on the reputation Wilson Combat barrels hold for accuracy, precision, fit & finish, and desirable features for the intended purpose of the rifle.
Many varmint rifles on the market feature a 24″ heavy profile barrel, and are sold on the premise that the longer barrel gives higher velocity. They are also marketed to suggest the extremely heavy profile makes for a more accurate rifle. The problem is that 24″ is beyond the point of diminishing return for many commercially available loads. The 5.56/223 is optimized for a 20″ barrel, and in some cases, a 24″ barrel can actually cause a loss of velocity due to friction. There may be a specific load that a 24″ barrel likes, and can deliver very high velocities from, but it certainly reduces the number of ammo choices that can be used. There are a few benefits to choosing an 18″ barrel. The overall length of the rifle will be decreased, which is not normally a problem for this type of rifle, but considering that I will eventually run a suppressor on this gun, that extra length will be magnified. 18″ is still plenty of length to get close to a complete powder burn, and I will be losing some weight without sacrificing rigidity. Theoretically speaking, a shorter barrel is a more rigid barrel without having to increase the diameter. By choosing an SPR profile, 18″ barrel, I am losing more than a pound of barrel weight. While some may not mind that extra pound of barrel weight, keep in mind that this rifle is going to be fairly heavy, and every extra ounce of weight will add up quickly. If I have to hike 5 miles to find the perfect piece of public land to hunt for coyotes, I will be glad I shed the extra pound.
The muzzle device that will be used at this time is a VG6 Precision Epsilon 556. This compensator does a great job of reducing recoil, while retaining some flash suppression. The overall length and weight of this muzzle device is surprisingly short and light for the performance when compared to similar muzzle brakes or compensators.