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The SR-556 Ruger’s Own AR-15 Style Rifle

During the past two years, Sturm, Ruger and Company has stormed the law enforcement market with new firearms that have proven incredibly popular with police officers. The three most recent are brand new firearm designs. The full-sized SR9 is a feature-packed 9mm pistol well-suited for police duty. The pocket-sized LCP .380 has become a favorite backup and off-duty weapon for law enforcement. One in five officers in my department now carries the LCP auto. Officers who prefer a revolver have not been ignored either. The introduction of the .38 Special +P LCR boasts a polymer frame and a light double action trigger pull.

Ruger played its cards close to the vest prior to the introduction of its latest firearms. When the announcements were made, the actual guns were already in production and in the process of being shipped. This marketing strategy meant that potential customers could read about the gun through advertising and then drive straight over to the local gun store to check it out for themselves (if it wasn’t already sold out).

Ruger’s Web site displayed a clock that counted down to the 2009 National Rifle Association’s (NRA) Annual Meeting. Internet speculation ran wild on police message forums as everyone tried to guess what was coming next from Ruger. I happened to be off from patrol that day, so I logged on to Ruger’s homepage before the clock wound down to noon. Apparently everyone else had the same idea because the page crashed at 12:00 p.m. It’s obvious there’s plenty of interest in Ruger firearms.

AR-15 Pattern Patrol Rifle

Initially, it may seem odd that Ruger would produce an AR-15 style rifle. After all, it has been making its Mini-14 rifle, firing the same 5.56 NATO (.223 Rem) cartridge, for decades. It would seem that an AR-15 pattern rifle would be in direct competition with a rifle they already offer, but the AR-15 is the hottest selling platform on the market.

Many police agencies already carry an AR-15 as a patrol rifle, and more departments continue the trend every day. Once Ruger’s Web site was back up and viewers were able to digest the new SR-556 (abbreviated from Sturm, Ruger 5.56mm cartridge) rifle, comments ranged from “Who needs another AR?” to “The suggested retail price of $1,999 is way too high.” The goal behind cutting out a big slice of the AR-15 pie was to build an innovative rifle with the features law enforcement desired most. Ruger should be able to cut out a pretty big piece of that pie with the rifle they have spent the last two years creating.

The Offensive Rifle for Patrol

The modern day police handgun is for defensive work, just as the Colt Single Action Army revolver was for marshals and sheriffs on the frontier over 100 years ago. The concept of a shoulder-mounted offensive weapon firing a single projectile accurately from a distance makes perfect sense today. The patrol rifle has come a long way since the old .30-30 Win lever action rifle helped enforce the law of the land. Instead of a horse’s saddle scabbard, police officers in the new millennium use an electronic storage rack in their squad cars.

Rifles provide the advantage of distance, and distance is always your friend in an armed encounter. Most police-involved shootings occur at close distance and often without warning. But, when responding to a “man with a gun” report, patrol officers and tactical teams know they need to stay out of the kill zone. We do not want to engage a subject who is armed with a handgun with merely a handgun of our own. We certainly don’t want to take on an offender with a rifle without a rifle of our own. If you can take an accurate shot from farther than the threat can take one at you, the advantage is yours.
Well-known Border Patrolman Bill Jordan once said that the advantage of the duty handgun is its avalability and portability. Your sidearm is holstered within quick reach, but if you knew there was a good chance that you might be in a gunfight, you’d bring a shotgun or a rifle.

For many decades, the pump action shotgun was the long arm most commonly mounted in squad cars. But its shot pattern expands quickly as distance to the target increases. A shotgun is an excellent choice for certain situations, but shot pellets can stray past their intended target and impact unintended bystanders. Firing slugs out of a shotgun turns the weapon into a rifle with very heavy recoil. It’s better to use a rifle than to try to make a shotgun act like a rifle.
Police departments in the U.S. began equipping their squad cars with patrol rifles in earnest during the late 1980s, and the trend has continued as more manufacturers have addressed this need. Savvy law enforcers patrolling wide open spaces stored lever action rifles and military surplus .30 caliber M1 Carbines in their squad car trunks when backup was not likely to arrive quickly.

The Marlin Camp Carbine, Ruger PC9 and PC40 carbines, H&K MP5, Beretta PX4 Storm and even the occasional Thompson .45 ACP have served as patrol carbines over the years. These short guns are chambered in handgun calibers and offer excellent performance at 50 and even 100 yards. But at more than 100 yards, a true rifle caliber is desirable for accuracy and energy transfer. The use of the AR-15 style rifle has increased tremendously in police patrol use.

Loaded with Features

Many police departments allow individual officers to carry a personally owned rifle (POR). If a department does not issue a handgun (or a backup or off-duty weapon), but instead requires its officers to purchase their own weapons, it is reasonable to allow officers to possess their own rifles as well. Most officers who are not issued a department-owned sidearm are allowed to choose from a department list of approved firearms. As long as they have trained and qualified with the rifle, they can have it accessible for patrol or tactical use.

I know several officers who “built” their own patrol rifles using parts from various manufacturers. They combined one maker’s “upper” with another’s “lower” and connected them with various aftermarket parts. This type of “parts” gun could be a civil suit respondent’s worst nightmare. While smaller AR-15 manufacturers will custom build a rifle to an officer’s specifications, the price tag can get rather high.

Ruger studied the current AR-15 market and figured out which features were most popular. They then cherry-picked some of the most well-known and respected manufacturers and used their products to bring forth the SR-556.

Piston Driven Operating System

The SR-556 may look and handle like all other AR-15 rifles, but it offers a radically different advanced piston driven operating system. Eugene Stoner’s gas impingement recoil operation functions well, as long as it’s kept clean and lubricated. But police officers (and the military) dread cleaning their rifles after a long day of range training. Soaking and then scraping bolts and chambers is difficult and tiresome work.

The new SR-556’s action is driven by a two-stage piston of Ruger’s own patent-pending design. The piston, its transfer rod, the bolt and the carrier are all chrome-plated. The hard chrome is extremely durable, wipes clean and requires little lubrication. When fired, gas is bled from the barrel into the gas block, propelling the piston rearward into the transfer rod. This transfer rod then actuates the bolt by pushing on an integral, raised, flat contact point.

This contact point is milled as part of the entire bolt carrier and eliminates the standard key screws that have separated and failed in other AR-15 designs. Dirty gas and fouling is kept away from the chamber area due to the use of the mechanical transfer rod. The rest of the bolt rotation and unlocking process functions the same as any other AR-15.

The SR-556’s gas piston also utilizes a four-position regulator which allows manual adjustment. Just forward of the front sight is an arrow on top of the gas tube. Turning the knurled adjustment knob changes the amount of gas flow through the gas port. Setting it to “0” shuts off any gas, and the bolt stays forward when a shot is fired. The charging handle can then be pulled by hand to recover the spent brass case.

The number 1 position might work fine for some factory ammo or custom handloads, but Ruger recommends the number 2 setting for most factory ammunition. Cranking up to setting number 3 is for when the weapon is extremely dirty after extensive firing, or if it is subjected to sand, mud or other grime.

The Best from the Aftermarket

When shouldering the SR-556, you take a comfortable and firm hold on the Hogue finger groove Monogrip. This hand-filling soft rubber grip is one of the best available. Your offhand also retains the forearm comfortably, thanks to the Troy Industries rail covers. Three provided covers slide on and snap right into place on the 10-inch Troy quad aluminum rail. This quality rail free-floats the barrel and is vented for optimum barrel cooling.

All four sides are numbered, which allows replacement of optics and accessories in the same place every time. If a police department has 15 rifles, it can state that an electronic sight will be mounted on top at T10, a tactical light on the left at L40 and a vertical grip on the bottom at B26.

A Mil-Spec buffer and recoil spring is housed inside the M4 style collapsible stock. The stock is quickly adjustable with six positions. This allows the gun to be used as a true shoulder-fired rifle when extended to its full length, or as a Close Quarter Battle (CQB) tactical entry weapon when shortened for use while wearing a bulletproof vest. The stock has a sling attachment at its toe but does not have one at the end of the forearm. I prefer a single point sling, so I replaced the plain receiver end plate with one that provided an attachment ring.

The tough aluminum and stainless steel battle sights are also made by Troy. The rear aperture is windage adjustable and has both a ghost ring and a smaller peep sight that flips up. The rear sight lines up quickly with the protected front post sight, which is adjustable for elevation. Each click for the sights adjusts bullet impact ½ MOA.

These sights attach quickly to the MIL-STD 1913 Picatinny top rail, and they fold out of the way with the push of a side button. They then flip right back up with your thumb and lock back into place. Electronic red dot sights or scopes can be mounted and used between the Troy battle sights without removing them.

The 16¼-inch barrel is cold hammer forged in-house by Ruger and chrome-lined for accuracy and durability. It has a 1 in 9 inch twist to accommodate 55 to 62 grain bullets. A removable 2-inch flash suppressor combines to make the overall barrel length just over 18 inches. While this is long for tactical entry CQB and moving around corners, it is well balanced and just right for a patrol rifle used for more distant shots. Without its magazine, the rifle weighs just less than 8 pounds.

Because AR-15 magazines lift rounds from both left and right due to their double stack, there are two feed ramps cut into the chamber. They match up perfectly with polished M4 cuts in the lower receiver. These M4 ramps provide reliable feeding with various bullet profiles.

The SR-556’s upper and lower receivers are forged aircraft grade aluminum, finished in a matte gray-black. The standard thumb safety is located on the left side and has a 90-degree swing from forward-safe to vertical-fire. The fenced magazine release is on the right side along with the forward assist, case deflector and spring-loaded chamber dust cover.

The Ruger rifle comes with three 30 round Magpul polymer magazines. While any standard AR-15 magazine will fit the SR-556, Magpuls have proved to be the top of the line. They feature tough ribbed construction, anti-tilt followers and springs that hold a full 30 rounds without the need to “back off” a few rounds for reliable insertion. The rifle and magazines come secured by hook and loop fasteners in a soft zippered black case emblazoned with the Ruger logo in red.

Shooting Performance

I was able to compare the SR-556 side by side with a standard AR-15 while range testing at 25 yards. The 5.56 NATO round doesn’t have much felt recoil to start with, but the Ruger’s gas piston operation still had noticeably less. Keeping the sights on target was easily accomplished. I was able to place 30 rounds into the 10 ring on a standard silhouette while firing offhand as fast as I could reacquire my front sight. Most of the rounds actually went in the X ring. The long sight radius provided by the quality Troy sights definitely aided in accuracy.

I scoped the rifle with Leupold 3-9X VX-1 glass and test-fired cheap, Remington 55 grain commercial ammunition at 100 yards off a sandbag rest. The trigger pull is standard military and not super light like that of a bolt action target rifle. Even though the trigger broke at a consistent 7 pounds, 4 ounces with little take up and no over travel, 1½-inch groups were still accomplished.

This type of patrol-oriented carbine is not intended to be a sniper rifle with sub-MOA accuracy. But 1½-inch groups are outstanding for cheap factory ammo fired down a hot and dirty barrel. Handloaders would probably be able to shoot much tighter groups out of Ruger’s superb barrel with custom-made rounds. 

I fired 650 rounds of various manufacture without cleaning the rifle and experienced no malfunctions. The gun ran like a well-oiled machine, despite the fact that it requires very little oil. It stayed cooler than gas impingement system AR-15s, even when several 30 round magazines were fired in rapid succession.

My department, like many police departments across the U.S., recently hired new officers with military combat experience due to the War on Terror. It’s been interesting to hear the opinions of these Iraq and Afghanistan veterans. One officer immediately field stripped the weapon and inspected the bolt. Not knowing the SR-556’s new recoil system, he looked at the chrome-plated bolt and said, a bit confused, “Okay, this is very different from what I’m used to.”

I explained the gas piston system to him. The military veteran was impressed that, because gas (and carbon) is not directed into the chamber to operate the action, the bolt still appeared relatively clean after 650 rounds. His next questions were “How much is it?” and “Where can I get one?”

The SR-556 comes with quality components from Hogue, Magpul and Troy Industries, in addition to the four-position gas piston operating system. The staggering array of accessories available for the AR-15 platform all attach to the Ruger just as they interchange with any other make or model. Ambidextrous safeties, red dot electronic sights, match triggers, winter trigger guards, tactical lights, lasers and many other options can all be added to customize the SR-556.

A popular nationwide retail store sells the rifle for $1,599, compared to its $1,999 MSRP. Adding up the cost of all the Ruger features (including a basic aftermarket gas piston system, not Ruger’s adjustable four-position system) would cost around $1,164. To build your own gun to approach the standard SR-556, you would need to buy a base rifle for just $435. Even a respectable used AR-15 is going to cost more than that.

In addition to its attractive price, another advantage of the Ruger is that it’s a factory-built rifle system that includes all the usual options as standard equipment. The civil court liability involved with a parts-built gun, assembled by an individual officer, is thwarted with this rifle that is mass-produced by a respected major firearms company.

The Ruger SR-556 offers a state-of-the-art, American-built patrol rifle at a price that includes the options most police officers desire in a POR. Ruger’s 60-year reputation for quality and service offers confidence that is difficult to put a price tag on. Officers were so impressed with the SR-556 that they wondered how much they could sell their current POR for, with the intent of purchasing the Ruger. The SR-556 is cut out to be a very satisfying slice of the AR-15 world’s pie.

Steve Tracy is a 21-year police veteran with 19 years of experience as a firearms instructor. He is also an instructor for tactical rifles, use-of-force, less-than-lethal force and scenario-based training. He can be reached at

Published in Law and Order, Jan 2010

Rating : 9.4

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SR-556E Economy Model Introduced

Posted on : May 27 at 6:47 AM By Steve Tracy

Ruger now has a more economical version of their gas pistol rifle called the SR-556E. The Troy Quad Rail and Troy folding iron sights are eliminated and a few other small items the bolt is black oxide instead of chrome are changed to bring the price down. The SR-556E is a great choice for those without a need for the quad rail that would be mounting an optic anyway.


Posted on : Dec 27 at 6:49 PM By Steve Tracy

Ruger announced the availability of Uppers in both .223 standard and carbine barrel lengths as well as the 6.8 SPC caliber. Theyre on sale now for $1,195 on Rugers website. The Uppers include everything on the SR-556 rifle piston driven system, Troy rails and sights.

New Caliber Available

Posted on : Aug 25 at 7:36 PM By Steve Tracy

Ruger has announced the availability of the SR-556 in the 6.8 SPC caliber as well as the standard 5.56mm/.223 Remington caliber.


Posted on : May 23 at 9:25 AM By Steve Tracy

Ruger just introduced the SR-556c at the May 2010 NRA Annual Meeting in Charlotte. The new version features a lighter weight fluted barrel and the overall barrel length is now just 14 with a non-removalbe flash hider 2 totalling the overall barrel length at the minimum legal length of 16. This should make the c version shorter and quicker to move during CQB.

USAF Retired

Posted on : Feb 11 at 8:15 PM By Dave M.

very very good article thank You!

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