To make this .223 product capable of winning Service Rifle matches, shooters should heavily—but legally—modify it.

Most everyone knows the general history of the AR15. It started life as an Air Force sentry rifle, was adopted as the M16 by our Armed Services, & went to Southeast Asia, where it got a bad reputation as a finicky, poor-shooting combat arm. However, some of the bad rap laid on the gun wasn’t deserved—witness that it has been the country’s primary battle rifle for more than two decades.

Nonetheless, the AR15 gained respect slowly, even though many manufacturers, including Colt’s, Ultra Arms, Springfield, and others manufactured millions of AR15s and AR15 clones. Despite their wide commercial acceptance, AR15s simply weren’t considered to be dangerous accuracy firearms, especially for competition shooting.

In the last two years, however, that attitude has changed. Upgrades for the gun now include heavier barrels, better sights, & all manner of configurations suited to different combat circumstances. Civilian-produced variations for High Power Service Rifle competition offer an even greater array of options. If you know which of the available race options deliver the most accuracy and functionality, you can get a lot of bang for your buck—producing a smooth, reliable, X-ring-shooting rifle in the process.

We decided to investigate what some of the top AR15 shooters in the country have done to their rifles to make them fit for use in High Power Service Rifle competition.

Here are the major modifications we found on the top guns:

Barrel Modifications
To simplify nomenclature, we will call all variations on the semi-auto .223 battle rifle AR15s, because for our purposes they’re the same gun.

Unlike the match-grade M14, which owes its success to military-sponsored engineering, today’s competitive AR15 was developed in the private sector. Borrowing from a long history of the M1, Army and Marine Corps engineers, contractors, and gunsmiths developed the competition M14 modifications, opened a market for barrels, stocks, & other upgraded components, & even developed appropriate ammunition.

The AR15, on the other hand, lay dormant in the military scheme of things while civilians pursued the transformation process from jungle gun to target rifle. Despite early explorations into the potential of a longer-range .224 (like the 1968 SALVO project and 1971 experimental AR15s developed by Rodman Laboratories at Rock Island Arsenal), & even the more recent development of the A2 rifle and SS109 63-grain combat round, whatever attention the military might have been turning to the AR15 didn’t change a thing on the tournament firing line. The M14 ruled.

The M14’s big disadvantage is that it requires a good deal of traditional gunsmithing & many labor-intensive modifications unique to the rifle to get it to shoot. For the military, that wasn’t a problem, because the AMU has a cadre of top-notch armorers and gunsmiths to keep the M14s running and gunning. In contrast, getting the AR15 up to speed requires nothing more than quality parts replacements. A specialist should still fit These new parts, but the technical challenges in fitting new parts simply aren’t on par with gunsmithing the M14.

The first thing to replace on most production AR15s are the barrel systems. The biggest problem stems from the gun’s hand guard design—the sling swivel is attached to the handguard front cap, which is appended to the barrel. No matter how heavy a barrel is, pressure points along its length influence bullet impact. Placing different tension against the sling swivel, as is done in the position-style shooting, changes where the barrel looks as the bullet leaves the muzzle, causing the gun to shoot erratically.

A tubular handguard pioneered 25 years ago on the Rodman Laboratories gun cures the problem. The tube can either replace the barrel nut or attach to a modified barrel nut. Thus, the sling swivel attaches to the handguard,& that cures barrel-stress problems. The barrel free floats & is immune from pressure-induced impact shifts. Also, because the “under tube” sits beneath the standard issue handguards, the guns’ exteriors maintain their OEM appearance as specified in Service Rifle competition rules. Turner Enterprises charges $160 for the Service rifle handguard & its installation.

Though it’s common for a Colt HBAR & other AR15s to shoot sub-MOA out of the box, it’s frequently necessary to buy a custom barrel. Many top shooters believe the best barrels come out of places like Boots Obermeyer’s shop, or from the barrel-making firms of Medesha & Krieger, all of whom are experienced in producing barrels for across-the-course High power rifles. Though prices the best shops charge vary according to the particular blank you buy, expect to pay around $400 for Obermeyer, Medesha, and Krieger tubes.

The Only Trigger You Need
When you consider buying replacement triggers for AR15s, there’s only one name you need to know: Milazzo-Krieger. The patent-pending M-K II trigger transforms the creepy AR15 stock trigger into a winning system. The Army Marksmanship Unit uses it, as do all serious AR15 shooters.

The M-K II trigger is a two-stage affair that borrows heavily from the basic concepts recognizable in the M14 unit, but that’s short-selling the engineering. This is not a modified AR15 trigger, but a complete system replacement. The M-K II is adjustable &, set at the Service-legal minimum of 4.5 pounds, feels like a lot less.

As many shooters know, the value of a two-stage trigger is that it feels effectively lighter in use. When you attach a trigger-weight gauge to a single-stage trigger, all of the force necessary to release the sear must be concentrated at the break point. In other words, you must pull 4.5 pounds all at once to make the trigger fire the rifle.

In a two-stage trigger, the required weight is distributed over a gradual take-up first stage & the sear-breaking second stage. The first step added to the second stage can yield a total of 4.5 pounds. A well tuned two-stage trigger can get about half of the required 4.5 lbs out through the first stage take up. With a two-stage trigger, you can effectively break a shot with what feels like 2 to 2.5 pounds of force on the trigger.

Milazzo-Krieger sells the M-K II for $190.

Sight refinement is another area in which a suitably modified AR15 can maintain an advantage over the M14’s rear view. Some M14 sights have precision movements, but many do not. Furthermore, even the best M14 sights sometimes decide they’re tired & become erratic at the most inopportune times.

The scenario usually goes like this: The shooter puts on or takes off a click of wind & fires a shot onto the same point he just corrected from. He then adds another click & fires the next shot out the other side of the target. The problem: The first click he put on or took off didn’t “take” until either recoil or another twist on the knob forced it to engage. Then he got two clicks rather than one, and may have lost two points in the process—& still doesn’t know where the rifle is shooting. This problem is a slight design flaw & can only be remedied by a perfect M14 specialist working with right parts. However, the replacement AR15 sights mentioned below have proven to track with Anschutz-level precision.

The AR15’s stock E2 upper receiver finally provided elevation adjustment at the rear sight, while simultaneously providing a platform to which right match-standard sights can be added.

By replacing the sight’s base & stem, elevation adjustments can be refined from about 1.5 minutes per click down to 0.25 minutes. Most Service shooters go with 0.50-minute clicks. Turner sells a rear-sight half-minute elevation kit for $80. (Windage clicks are already set in half-minute increments, so there’s no need to change the horizontal adjustment mechanism.)

Also, the rear aperture can be modified to one with a smaller hole, which provides a better sight picture. Turner’s two-aperture rear view conversion runs $40. To enhance the rear view performance further, try one of Turner’s rear aperture setups. This feature threaded interchangeable aperture inserts which are Service legal but allow the shooter to tune the rear sight to lighting conditions.

Next, the overly full AR15 front sight can be chucked into a drill (lightly) and spun on a stone to whatever width the shooter prefers, or various front view size replacements are available from Accuracy Speaks & Turner Enterprises.

The replacements run about $17. Either way, be sure to secure the front sight (it can shift) using light-duty thread locker or by tapping the front sight threads fully through. Install an 8-36 lock screw of an appropriate length from underneath the sight & snug it down. This will close the sight in.

Things You Don’t Need
In this discussion of accurizing the AR15, you might have noticed there was no mention of bedding, action truing, bolt lapping, or other more traditional accuracy-enhancing procedures, & that’s because they’re not needed. Make no mistake: Those procedures been tried, and they don’t work.

The AR15 breaks the traditional High Power gunsmithing rules, as is evidenced by its upper & lower receiver fit. It makes sense to believe that a perfect mating of these parts would “tighten” up the gun & make it shoot better. Quite the opposite. As ace AR15 builder Derrick Martin of Accuracy Speaks says, “It seems that the more the AR15s rattle, the better they shoot.” He says attempting to mate the parts leads to metal-to-metal binding along the receiver junction, which hurts accuracy.

The AR15’s simple, efficient design is making the guns last longer, too. The AMU gets 7,000 rounds of good performance from an AR15 barrel before it won’t clean at 600 yards—about double what was expected from an M14. And that’s with nothing more than normal maintenance.

PFS Recommends
Get these changes made to your AR15, & you have what the AMU shoots—which is to say you have a rifle that’s capable of winning Camp Perry. You may ask why it’s necessary to buy a combat rifle that has cost as much as $2,000 in recent years and then add another $1,000 to its bottom line cost. The answer: High Power Service Rifle competition has always been, and hopefully will always be a skill contest. But if your equipment doesn’t match up with what the countries best are firing, then you have no shot at all. To win with the AR15, or even to be competitive, the gun must be upgraded—how much you spend depends on how much you want to win.

-By Glen Zediker


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