Ruger AR-556 in 5.56 NATO Part I

Rounds to the pound and familiarity

A number of years ago, as results of a less disciplined life, I became diabetic with an A1C of 11+, complete with arteries that took on the appearance of a clogged oil filter and blood pressure of 1000/Good Grief!. Examining the alternatives, a healthy diet… ugh and exercise.. ugh, became a part of my life. So my wife and I researched, reduced our findings to a three ring binder filled with appropriate meal recipes and food selection, and organized them so that any selection would provide only the correct levels of calories, cholesterol, sodium, and carbohydrates.

Today, A1C is below 5.7% without medication, my blood pressure is below 120/70 without medication and I can walk on a treadmill’s steep grade at 3 MPH for half an hour without breaking a sweat or becoming winded. I have not been one pound overweight for the past four years. OK, so I no longer entertain my family by clutching at my chest, falling to the floor and gasping for air like a bass out of water but, as a trade off, I can now walk the woods, enjoy firearms and enjoy this time with my wife and family. This is intended as a not too subtle message to other guys who get too busy to take care of themselves – never too late.

My point is that decisions that determine survival should not be made in haste, or in the midst of a crisis. It is not a good idea to wait until hunger pangs have set in before determining a menu. Just like it is not a good idea to wait until your family or your home is in jeopardy before thinking about what you will use to marshal a defense.

The case for the factory standard egg… Err… AR

Secured in one home location are AR 15 types chambered for the 6.5 Grendel, 300 Blackout, 350 Legend, and 450 Bushmaster. Secured in another location and stowed with other essential gear, is a lone Ruger AR-556 MPR chambered for the 5.56 NATO. Why? The first location is filled with firearms that are good choices for hunting, recreational target shooting and handloading projects. The second firearm represents a pragmatic choice I’ve made that will best serve in a crisis.

My interest is not to suggest use of a specific firearm, but rather that there is no time like the present to select the firearm that may determine your survival and the survival of those important people around you. One day, we may wake to a population turned into zombies, as has already happened in most of our larger cities, or even to a Maine population that has left for Florida in anticipation of winter, leaving us to our own devices.

 

Ruger AR-556 Multi Purpose Rifle

Manufacturer Sturm, Ruger & Co.
Point of Manufacture Mayodan, NC
Model# 8542
Caliber 5.56 NATO / 223 Remington
Mag Capacity 30 Round Magpul PMag
Barrel Length 16.1″ Light Contour 4140 CM
Rifling 1:8″
Weight 6.7 Lbs
Overall Length 33″ – 36.5″
Stock Collapsible
Receivers 7075-T6 Aluminum Forging
Receiver Finish Type III Hard Coat Anodized
Barrel & Gas Block Matte Black Oxide
Length of Pull 11.1″ – 14.4″
Accessory Mount Picatinny Rail
Trigger Pull 4 Lbs. 11 Oz. Single Stage
Safety Rotating
MSRP $899

A Ruger AR-556 MPR was selected, based on experience with the product and the company that makes them. Ruger materials, processes and purchase parts are exceptional and it shows in the quality of: castings, molded pieces, extruded pieces, piece parts, and finishes. Overall product quality and attention to detail shows in the final assembly.

Ruger refinements appear in areas like the buttstock, floating handguard and fire control components. However, in a pinch, mil spec standard pieces could be used to service and repair the AR 556.

Available also in 350 Legend and 450 Bushmaster, the 5.56 NATO version was selected because the ballistics were appropriate for foreseeable applications, ammunition is widely available in many forms, and because ammunition is relatively light. My assembled handloads yield 40 rounds per pound, the 350 Legend handloads are 26 to the pound and the 450 Bushmaster handloads are 18 rounds to the pound.

The moderate pressure 5.56 NATO round is light for the AR 556 system, whereas the other calibers tend to put more stress on the system and accelerate wear. Additionally, the power of the larger cartridges is not required for the application so the excess weight and reduced availability offer little as a trade off.

The tight 8″ rifling rate of twist will stabilize bullet weights between 35 and 77 grain. The 16.1″ barrel also means that 6″ – 8″ of silencer attached will not make the rifle feel duck blind ready.

The Ruger is light, the stock is collapsible, there is just enough Picatinny rail and handguard M-Slots to attach anything useful without getting in the way or turning in to a giant cheese grater.

A very well thought out  and complete AR system

The AR 556’s 4140 chrome moly barrel has 5R rifling for minimum bullet deformation and ease of maintenance. The barrel has M4 feed ramps and the chamber accommodates both 5.56 NATO and 223 Remington ammunition. The mid length gas system provides reliable operation at lower gas pressure than a carbine length gas system. The barrel’s muzzle has 1/2″-28 threads to accommodate the supplied Ruger radial port muzzle brake, silencers and similar types of devices; things stowed with the Ruger AR-556.

The AR-556 MPR floating handguard is a lightweight 13.50″ aluminum piece. It contributes to both accuracy and the firearms light weight and it provides M-LOK® accessory attachment slots at 3:00, 6:00 and 9:00 positions. By placing rail segments at either end, but clear of the center, the handguard accommodates all accessories, but is clear of gripping surfaces. The long barrel nut mounts the floating handguard as part of a secure, yet simple system.

 

Ruger AR-556 receivers are 7075-T6 hard-coat anodized aluminum forgings for durability. The receiver integral top rail, and handguard rail segments, permit the use of metallic sights, red dot sights, scopes, and infrared sighting devices; all devices stowed along with the AR-556.

The grip is a B5 Systems Type P23, the buttstock is a Bravo collapsible, mounted on a mil-spec buffer tube. The stock offers good face support, a non-slip recoil pad and QD sling mounts.

The bolt is fashioned from 9130 steel, shot peened and proof tested as is the 8620 bolt carrier. The inside of the carrier and inside of the gas key are  chrome plated and the key fasteners are staked to stay put.

A substantially improved trigger…

The Ruger AR-556 MPR gets the two stage Ruger Elite 452 trigger in place of the standard single stage AR-556 trigger. The trigger is clean, has a relatively light pull, 4 1/2 lbs, and 30% fast lock time than a standard single stage AR 15 type trigger.

On the single stage side #1, the notch in the hammer is retained by #3, the primary sear. When the trigger is squeezed, the sear is pulled downward and the hammer is released to rotate forward to move the firing pin. If the bolt cycles the hammer before the trigger is reset, the secondary sear #4, engages the #2, the hook at the back of the hammer and prevents it from falling forward.

On the two stage trigger, the latching surface at the rear of the hammer #1, engages the primary sear #3. As the trigger is squeezed, the first part of trigger travel meets a light one pound resistance from the trigger spring and begins moving the sear away from hammer engagement. Then there is an increase in pressure as the backside of the hammer #2 contacts the nose of the secondary sear on the disconnector #4 and compresses the disconnector spring during the second stage of pull. The hammer’s secondary sear contact surface #2 was relocated, but functions the same.

Flexible configurations

 

At the moment, the subject Ruger AR-556 MPR is equipped with a 4.5-30 x 50mm scope on a low riser rail and with an AAC SR-5 silencer in preparation for live fire assessment. The plan is to wring it out with factory ammunition and then move on to the best handloads and firearm configurations for intended applications. Be back shortly with Part II.

 

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