Zediker Examines Long Range Shooting with AR-Platform Rifles
Looking to shoot an AR-platform rifle out past 500 yards? Then you should read two articles by AR guru Glen Zediker. Author of The New Competitive AR-15 and The Competitive AR15 Builders Guide, Zediker is an expert when it comes to AR-platform rifles. Glen believes ARs have excellent long-range capability, provided they are built to high standards, with good barrels.
Glen says: “a properly configured AR-15 is easily capable of good performance at 500+ yards. Good performance means it can hit a 1-foot-square target all the time. Competitive shooters can cut that standard in nearly half (the X-Ring on an MR1 600-yard NRA High Power Rifle target is 6 inches, and high X-counts are commonplace among more skilled shooters).”
Published in the Cheaper than Dirt Shooter’s Log, Zediker’s articles first cover the history of the AR-15, and then explain how AR-platform accuracy can be optimized. Part One reviews the AR’s development as an accurate firearm, tracing its evolution from a Vietnam-era combat weapon to what is now a favored target rifle of High Power competitors. READ PART ONE.
Part Two discusses the specifics that make an AR accurate at 500 yards and beyond. Zediker talks about barrel configuration (profile and twist rate), bullet selection, floating handguards, and proper mounting of optics or iron sights. READ PART TWO.
Here are some highlights from Long-Range AR-15 Part TWO:
Barrel Twist Rate
To stabilize anything longer than a 68- or 69-grain bullet, the barrel twist rate must be — at minimum– 1-in-8. Twist rates reflect how far the bullet travels along the lands or rifling to make one complete revolution. So, 1-in-8 (or 1-8, 1:8) means “one turn in eight inches.” I think it’s better to go a little faster in twist. There is nothing wrong with a 1:7 twist. The 90-grain bullets require a 1:6.5, and that is getting on the quick side. If you want to shoot Sierra 77s or equivalent, and certainly anything longer, 1:8 is necessary. By the way, it is bullet length, not weight, which constitutes the necessary twist rate to launch a stable bullet.Optics Mounting
Correct optical sight positioning can be a challenge. With a flattop upper, I need a good inch additional forward extension at the muzzle side of the upper for the sight mount bases to avoid holding my head “back” to get the optimal view through the scope. A longer rail piece is necessary for my builds as a result.Buttstock Length and Adjustment
An adjustable buttstock is valuable, and even more valuable if it’s well-designed. Mostly, a standard stock is too short, and the cheek area sits too low. Adding length helps a lot by itself. There are assemblies that replace the standard buttplate to allow for length and, usually, height and rotation adjustments for the buttpad. An elevation-adjustable cheekpiece is a big help to attain a solid position.
