SAFETY: Read and understand the safety warnings in the operators manual before you do anything else. Use good hearing protection, because the recoil check (muzzle brake) concentrates muzzle blast near the shooter.

IMPORTANT NOTE ABOUT YOUR LIMITED LIFETIME WARRANTY: The limited lifetime warranty is applicable to original, individual ArmaLite purchasers only. Institutional purchasers receive warranty support for a period of one year. THE WARRANTY BECOMES EFFECTIVE ONLY UPON RECEIPT OF THE WARRANTY REGISTRATION CARD PROVIDED WITH YOUR RIFLE. IF NO CARD IS ON FILE, ALL WORK WILL BE BILLED AT SHOP RATES.

GENERAL: ArmaLite’s .308 caliber (7.62 x 51mm NATO) AR-10B series rifles are the third series in a historic family. The first, designated AR-10, was designed in the late 1950s and entered production in the early 1960s. Only about 10,000 rifles were produced. The second series, the AR-10A, was an improved version that didn’t enter production. ArmaLite’s new AR-10B series is the latest and most up to date. The AR-10B series includes the classic AR-10B, the modern AR-10A2 Infantry Model, the AR-10A4 Flattop, and the AR-10(T) Match Rifle.

(Notice that the designation "AR-10B" is used two ways, causing confusion among some shooters. It designates the third, and most current, series of AR-10 rifles. In addition, it is used to designate a specific model within the new series. The rifles are all normally called "AR-10s".)

AR-10 rifles are very similar to ArmaLite .223 caliber M15 series rifles or the military M16A2 rifle. The manuals for either of those rifles generally pertain to the new AR-10s as well. Specific differences and additional facts include:

PATENTS and TRADEMARKS: The AR-10 rifle is protected by U.S. Patents 5,638,626, 5,911,173, and 6,044,748. AR-10 and variants are trademarks of ArmaLite, Inc.

FIRING PIN SPRING: The firing pin spring reduces the firing pin mark made on the primer as the rifle bolt closes. This mark is a characteristic of all Ml, M14/MlA, and M16 type Rifles. If a primer is overly sensitive, it is possible for it to fire when the bolt closes (a "slamfire"). The AR-10B firing pin spring makes slamfire virtually impossible (none have been reported) while maintaining reliable ignition. The design of the carrier group prevents a slamfire before the bolt is locked.

The tight end of the firing pin spring is slipped over the front of the firing pin first. It engages a groove on the firing pin, which prevents the spring’s loss. During assembly of the bolt carrier group, press the firing pin forward about 1/8 inch after feeling spring resistance. This allows the firing pin retaining pin to be inserted behind the large flange of the firing pin, and thereby hold it in position. THE FIRING PIN SPRING IS AN IMPORTANT SAFETY DEVICE AND MUST NOT BE LOOSE, REMOVED, OR LOST. ArmaLite will provide a free replacement if it is damaged.

FIRING PIN RETAINING PIN: Do not pound or force the firing pin retaining pin into position; it may be damaged. To check for proper assembly of the bolt carrier assembly, hold it with the bolt up to verify that the firing pin and spring don't fall out. Push forward on the rear of the firing pin and make sure that it is pushed back by the firing pin spring. Replace the retaining pin if it is damaged.

EXTRACTOR SPRING REINFORCEMENT: ArmaLite’s exclusive Extractor Spring Reinforcement Ring surrounds the extractor spring. Remove the ring if the rifle to be used at temperatures below 0 degrees Fahrenheit.

McFARLAND GAS RING: Like the 3-piece rings of the AR-15, the one-piece McFarland Gas Ring should be replaced if rifle functioning is sluggish (i.e. if the fired cartridges don’t quite eject.)

CAM PIN FIT: Tight tolerances on the AR-10 may require use of a flat tipped screwdriver or other suitable object to slip the cam pin past the bolt carrier key. The cam pin must never be altered to provide clearance.

INSERTING THE CAM PIN: When assembling the carrier group, insert the bolt into the carrier only enough to allow the cam pin to be inserted. Insert the cam pin straight into the carrier (you don’t rotate it 90 degrees like the AR-16 Cam). There is a groove inside the carrier, just ahead of the small diameter hole at the bottom of the gas cavity. Inserting the bolt too far into the carrier can cause the McFarland Gas Rings to expand into the groove. Removal might require the bolt to be driven forward with a brass rod, which can damage the rings. Once the cam pin is in place, the bolt can’t be pushed too far into the carrier.

LUBRICATION: ArmaLite recommends Bore Cote ™ , LSA (Lubricant, Semi-fluid, Automatic weapons) or other high-quality lubricants, especially on the highly-stessed Bolt Carrier Group. Lubricate the rifle generously.

MATCH TRIGGER ADJUSTMENTS: ArmaLite’s National Match trigger assembly isn’t user adjustable. For safety reasons, it is intentionally built with a small amount of creep in the second stage. As it breaks in with use (200 to 500 rounds) the creep tends to decrease to an acceptable level. If excess creep remains, the trigger can be tuned by a gunsmith using techniques similar to those used with the Ml/Ml4 trigger system. ArmaLite technicians will fine-tune the triggers for a nominal shop fee, plus shipping. We regret this inconvenience, but the current unpleasant state of tort law requires it.

PULLING THE TRIGGER: Failure to pull a target or match-grade trigger firmly can result in the shooter firing two shots. This effect is common to all self-loading firearms, and especially common to match triggers on common target rifles such as the M1 or M-14 National Match rifles.

With each shot the rifle moves rearward in recoil, then recovers forward in counter recoil. The trigger finger is a springy structure, and as the rifle recoils the trigger finger and the rifle move relative to each other just a little. If the hand and finger are held too loosely or if the trigger is pulled too delicately, it is possible that the moving trigger can push into the stationary trigger finger as the rifle moves forward. The finger isn’t moving, but the trigger is. The relative motion between the trigger and trigger finger can result in the shooter firing two shots before releasing the trigger. This is not a "double," but sounds like it. This error occurs most often when firing from a bench. To prevent this "false doubling," pull the butt firmly into the shoulder, grip the rifle strongly and pull the trigger aggressively. If false doubling continues or is frequent, ArmaLite will adjust or replace the trigger mechanism. Safe gun handling prevents a false double from causing an accident.

AMMUNITION: The AR-10(T) has a specially lapped match grade barrel. It is superbly accurate when used with Black Hills moly coated .308 Match ammunition, Federal .308M, G.I. M852, or other match quality ammunition. Accuracy naturally is less impressive if lower quality ammunition is used. ALMOST EVERY ACCURACY OR FUNCTION PROBLEM IS CAUSED BY FAILURE TO CAREFULLY BREAK THE RIFLE IN, FAILURE TO USE HIGH GRADE MATCH AMMUNITION, OR POOR MARKSMANSHIP.

BLOWN PRIMERS: Some .308 match ammunition is loaded for relatively high velocity, and some surplus ammunition is also suspect. An occasional round is unusually hot, or is made from soft brass. If the ammunition you use shows signs of primer flattening, gas leakage, loose primer pockets, or blown primers, try a more conservative lot.

BREAK-IN PERIOD: ArmaLite rifles are made more tightly than other rifles of similar design. A break-in period of 200 rounds allows machined or phosphate-coated surfaces to mate.

ArmaLite’s stainless steel barrels are produced from custom, triple-lapped target grade blanks. For optimum accuracy and improved life expectancy, they MUST be properly broken in. To do this, fire 11 single shots, each followed by about 20 strokes of a tight fitting patch bearing J-B bore cleaner (available from Brownells, 515-623-5401). Use a Parker Hale or other wrap-around style jag rather than a slotted jag. From 12 to 30 shots, clean after each 3 shots. From 31 to 50 shots, clean after each 5 shots. Clean thoroughly with a high quality bore cleaner every 10 shots until 100 shots. This time-consuming process will allow the barrel to smooth out without an accumulation of copper fouling in the pores of the steel. The barrel should thereafter be cleaned every 20 rounds for best match accuracy. Accuracy continues to improve for several hundred rounds as the rifle breaks in.

ArmaLite recommends Black Hills moly coated .308 Win Match ammunition for both break-in and competition. Black Hills molybdenum disulfide ("moly") coated ammunition reduces the break-in period to about thirty rounds (by pulling a dry patch through the barrel after each) and lengthens the period between cleaning. Contact ArmaLite to order this ammunition.  

FRONT SIGHT ADJUSTMENT TOOL: ArmaLite recommends that shooters use a front sight adjustment tool to zero their front sight blades, especially with the tight fitting removable front sight of the AR-lOA4 and AR-10(T).

ZEROING THE FRONT SIGHT FOR WINDAGE: Normal manufacturing tolerances can result in the rear sight being off- center when the rifle is zeroed. ArmaLite’s exclusive screw-clamping gas blocks (T and A4 models) and front sight bases (A2 models) allow the owner to zero the front sight for windage with the rear sight centered. To do so, put the rear sight in the center of the rear sight base. Fire a three-shot group. To adjust the next shot group to the left, loosen the clamping screws and shift the front sight to the right slightly. To shift the group to the right, shift the sight to the left. Tighten the clamping screws of the front sight base and finish zeroing in the normal manner using the windage knob of the rear sight. Elevation is adjusted by raising or lowering the front sight. Once the front sight is zeroed, turning the elevation knob sets the range.

PROTECTING BARE BARREL SURFACES: Shifting the gas block or sight base will normally expose a thin, line of unprotected steel inside the split base. This unprotected surface results from government regulations that render it impractical to phoshphate the barrel before assembly. Paint, oil, or another suitable protectant must protect it.

RATE OF FIRE: The rate of fire of the AR-10 is the equals that of the M-14 rifle in rounds per minute for a maximum period of:

2 minutes………………………………………..40 rounds per minute

10 minutes………………………………………30 rounds per minute

20 minutes………………………………………20 rounds per minute

30 minutes or more……………………………..13 rounds per minute

BARREL LIFE depends on how fast the rifle is fired, and how accurate the shooter insists it must be. Shooting the rifle as fast as the trigger can be pulled can ruin the barrel in just a few hundred rounds. Firing at controlled rates (see above) will allow a standard-grade AR-10 barrel to last for 10,000 to 15,000 rounds with accuracy acceptable for Police use. Target shooters fire at very moderate rates, but their higher accuracy requirements dictate 7.62mm barrel replacement by about 7,000 match rounds.

REMOVING THE AR-10(T) TUBULAR HANDGUARD: It should seldom be necessary to remove the tubular handguard of the AR-10(T). If it must be removed, a vise with protected jaws is useful. Begin by holding the rifle by the fiberglass tube. Use a strap wrench to grasp the lock ring at the front of the receiver. Loosen the ring by rotating it counterclockwise (as viewed from the butt), and pull forward on the handguard at the same time. Wrapping the lock ring with double-sided tape or duct tape, or wiggling the handguard slightly as it loosens may help. Reverse the procedure to install. WARNING: EXCESSIVE TIGHTENING OF THE LOCK RING WITH A STRAP WRENCH CAN LOOSEN THE BARREL NUT OR DEFORM THE GAS TUBE.

REMOVING THE AR-10A2 and A4 HANDGUARDS: The AR-10 slip ring is held forward by a stronger spring than those of .223 caliber rifles. Handguard removal may be a two-man job. It’s easiest to place the butt on the ground and push the slip ring back while a second person works the handguard panels loose. They should seldom need to be removed.

LOADING THE MAGAZINE: AR-10B magazines have a patented spring-loaded plunger in the follower. It engages the bolt catch to hold the bolt open automatically when the last round is ejected. Load the first round into the magazine normally. Press the plunger into its hole to insert the second round. Insert remaining rounds as usual. Some early 10 round magazines must either be unloaded or contain at least 2 rounds before they can be locked into a rifle when the bolt is closed.

INSERTING THE MAGAZINE: Smoothly press the magazine straight upward into the magazine well until the magazine catch snaps into place. Pull down on the magazine slightly to make sure that it is caught by the magazine catch. Contrary to Hollywood tradition, NEVER tap or pound the magazine into the receiver. Excessive pressure can force the magazine past the magazine catch.

USING M-14 RIFLE MAGAZINES: The AR-10B magazine is based on the proven M-14/MlA rifle magazine. A good quality metal 20 round M-14/MlA magazine can be altered to work perfectly in the AR-10B. U.S. G.I. and imported Chinese magazines are acceptable. Most commercial metal magazines with blue finish or pressed latch plates require replacement of the shell. Fiberglass magazines (i.e. Thermold, etc.) are totally unsuitable for conversion.

ArmaLite sells 20 round magazines when available. ArmaLite offers a variety of methods for converting customer’s M1/M14 magazines. Conversion kits are available to allow customers to convert their own magazines.

TIGHT FIRST ROUND: Due to design constraints resulting from 1994 Crime Bill, the cartridges in a fully loaded magazine are tightly compressed. If loading or operation are sluggish, reduce the number of rounds in the magazine by 1 (a common practice with the M14 rifle).

MAGAZINE INTERCHANGEABILITY: 10 round AR-10B series magazines and converted 20 round M-14 magazines will not work in the AR-10/AR-10A rifles made in the 1960s, or in the current SR-25 rifle made by Knight’s Armament Corporation. Magazines for those same rifles will not work in the current AR-10B series rifles.

CLEANING THE MAGAZINE: Disassemble the magazine carefully to avoid losing the spring-loaded Bolt Catch Trip in the Follower. Wipe clean and dry with a cloth soaked with a good bore cleaner. Lubricate sparingly. Make sure that the front and rear of the magazine shell are smooth.

RECEIVER FIT: The AR-10B is not a custom fit firearm. ArmaLite gets a close fit between the receivers, but normal forging and machining variations may result in play like that of .223 caliber M-16 style rifles, or slight side to side receiver mismatch. This is not a manufacturing defect and has no effect on accuracy.

FIXED MUZZLE BRAKE: All AR-10Bs are "Post-Ban" production rifles. The recoil checks (muzzle brakes) used on them are permanently attached in accordance with government regulations. DO NOT TRY TO REMOVE THE MUZZLE BRAKE: DOING SO WILL CAUSE SEVERE DAMAGE TO THE BARREL.

APPEARANCE: Almost all complaints concerning appearance come from customers who forget that the AR-10 is a Military Specification rifle, not a polished commercial-grade rifle. They are industrial products, not custom rifles, and bear simple finishes.

ArmaLite rifles are all thoroughly test fired before shipping. New rifles will normally show evidence of this firing. If the receiver looks light or uneven, it’s probably dry. A light coat of oil on the anodized surface will cure the problem.

The anodized surface of new ArmaLite rifles bears a matte finish. This surface can be scuffed or polished, but the base layer of hard coat anodizing (at Rockwell C 60+) is undamaged. After repeated cleaning, the receiver assumes a semigloss finish quite similar to the early AR-10 rifles. Various soft plastic cleaning pads and oil may be used to "polish" the matte to bring the surface to a uniform sheen.

The receivers and front sights are made of forgings. Forging is a heavy industrial process that leaves small dents and dings on the forgings. ArmaLite inspects all forgings for excessive marks or deformation, but no forging is free of them. This is a normal condition of forgings, not a defect.