Bushmaster ACR Operating and Safety Manual ® ® ™
TABLE OF CONTENTS PAGE 1 2 3 4-5 6 7 8 9 10 10 11 12-13 14 15 16 17 18 Warnings/Cautions/Safe Handling Dangerous Procedures About Your Bushmaster Firearm Firearm Features & Controls – Identification/Location Clearing Your Firearm Preventative Maintenance Checks Safety Function Check Preparing to Fire/Loading a Magazine Operation of Your Firearm/Loading Operation/Inserting a Magazine Operation/Chambering from Open Bolt Operation/Chambering from Closed Bolt Operation/Stock Adjustments Immediate Actions - In
PLEASE PRACTICE SAFE FIREARMS HANDLING! WARNING: IF THIS FIREARM IS CARELESSLY OR IMPROPERLY HANDLED, UNINTENTIONAL DISCHARGE COULD RESULT AND COULD CAUSE INJURY, DEATH, OR DAMAGE TO PROPERTY. CAUTION: CAREFULLY READ THIS INSTRUCTION MANUAL PRIOR TO LOADING AND FIRING THIS FIREARM.
WARNING: BEWARE OF DANGEROUS PROCEDURES • Be sure Cam Pin is installed in the Bolt Group. If it isn’t, your Firearm can still fire and COULD MALFUNCTION CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR DEATH. • When using a Blank Firing Attachment, NEVER FIRE ANYTHING EXCEPT BLANKS! For your safety, we recommend the visible, military style blank firing attachment (BFI Part# RAY-008).
ABOUT YOUR BUSHMASTER RIFLE… This Operating Manual covers the Bushmaster ACR (“ACR”) which is chambered in 5.56mm NATO/223 Remington and 6.8mm Remington SPC ammunition. It is a gas piston, air-cooled shoulder fired, magazinefed Firearm, that is Semi-Automatic in operation (i.e., a single round will fire each time the trigger is pulled). • The ACR Barrels are cold hammer forged and hold the tightest tolerance allowed.
Firearm Features & Controls - Identification/Location… MBUS Front Flip Sight MBUS Rear Flip Sight Adjustable Cheek Piece Brass Deflector Monolithic MIL-STD1913 Top Rail Gas Regulator Selector Compensator Safety Selector Fixed High-Impact Composite A-Frame Stock with Rubber Buttpad 4 Composite Polymer Hand Guard Trigger Pistol Grip Magazine Release Button 30 Round PMAG Bolt Catch/Release
Firearm Features & Controls - Identification/Location… (cont’d.) Charging Handle M4 Profile Barrel Quick Detach Sling Coupler Hand Guard Retaining Pin Pivot Pin Takedown Pin Stock Release Pin Quick Detach Sling Coupler Safety Selector Sling Loops Magazine Release Button Bolt Catch/Release NOTE: ATF Regulations require a minimum barrel length of 16" on commercially available rifles and carbines.
CLEARING YOUR FIREARM… ALWAYS FOLLOW THE RULES OF SAFE FIREARM HANDLING. First, assume the firearm you are handling is loaded, and then proceed - according to the following steps - to CLEAR YOUR FIREARM . . . 1. Point Firearm in a SAFE DIRECTION! Place Safety Selector Lever on SAFE. NOTE: If the Firearm is not cocked, the Safety Selector Lever cannot be pointed toward SAFE. 2. Press Magazine Release Button and pull Magazine down to remove. 3. To lock Bolt open, pull Charging Handle rearward.
PREVENTATIVE MAINTENANCE CHECKS & SERVICES… CHECK BEFORE YOU FIRE! ALWAYS FOLLOW THE RULES OF SAFE FIREARM HANDLING. First, assume the Firearm you are handling is loaded, and then proceed - according to the following steps to CLEAR YOUR FIREARM... 1. Check to see that there is NO EXCESSIVE OIL in the Bore. If there is, swab it out with a patch and the cleaning rod. ALWAYS CLEAN A NEW FIREARM BEFORE FIRING.
SAFETY FUNCTION CHECK… UNLOAD FIREARM - REMOVE MAGAZINE - CHECK CHAMBER 1. Remove Magazine if installed. Pull Charging Handle assembly to rear. Check that Chamber is clear. Let the Bolt and Bolt Carrier close. Do not pull Trigger. Leave Hammer in cocked position. WARNING! If Firearm fails any of the following tests, continued use of the Firearm could cause a malfunction causing personal injury, property damage or death. 2.
PREPARING TO FIRE - LOADING A MAGAZINE… 1. Use only quality 5.56mm/223 Remington Ammunition in your Firearm (or 6.8mm Remington SPC if applicable). Examine each Cartridge - particularly around the primer. Look for dents, scratches, and other signs of damage. DO NOT LOAD DAMAGED AMMUNITION! 2. With the Magazine facing forward, as shown in the illustration, place a Round between the Feed Lips of the Magazine with the Bullet Tip forward. Push the Round down until it is held by the Magazine Feed Lips. 3.
OPERATION OF YOUR FIREARM… LOADING CAUTION: ALWAYS POINT THE MUZZLE IN A SAFE DIRECTION! 1. With the Hammer cocked, place 2. Open Bolt and check Firing Chamber. Selector Lever on SAFE. Make sure it is CLEAR! INSERTING A MAGAZINE… 1. Return Charging Handle to forward, locked position. Push Magazine up into Magazine Well until Magazine Catch engages and holds the Magazine. 10 2. Slap upwards on Magazine bottom to make sure it is seated correctly.
OPERATION OF YOUR FIREARM… (cont’d.) CHAMBERING A ROUND FROM AN OPEN BOLT… NOTE: The Magazine may be inserted into the Firearm with the Bolt Assembly Open or Closed. 1. Press the Bolt Catch downward. Bolt should spring forward. This will chamber a round from the Magazine. 2. TAP the Charging Handle forward with the heel of your hand to ensure that the Bolt is fully forward and locked.
OPERATION OF YOUR FIREARM… (cont’d.) CHAMBERING A ROUND FROM A CLOSED BOLT… 1. With a Magazine in the Firearm, pull the Charging Handle fully to Rear. Then release the Charging Handle – allowing the Bolt to spring forward – chambering the first round. NEVER “Ride” or push the Charging Handle forward. Let it move forward on its own. 2. TAP the Charging Handle forward to ensure that the Bolt is fully forward and locked.
OPERATION OF YOUR FIREARM… (cont’d.) CONDITION: Firearm is now Loaded, a Round is chambered, and Safety Selector should be on SAFE. CAUTION: ALWAYS POINT THE MUZZLE IN A SAFE DIRECTION! To FIRE the Firearm in SEMI-AUTOMATIC MODE (one Round fired with each pull of the Trigger), move the Safety Selector Lever from SAFE to FIRE. Aim at Target – Pull Trigger – Release. The Firearm will automatically eject the spent Cartridge and chamber another Round in preparation for the next shot.
OPERATION OF YOUR FIREARM… (cont’d.) STOCK ADJUSTMENTS 1. To adjust the Cheek Piece height, slide the Cheek Piece rearward to unlock. 2. Lift Cheek Piece to the elevated position. 3. Slide Cheek Piece forward to lock into place. 4. Reverse action in order to return Cheek Piece to the lower position. 2. 3. OPTIONAL – FOLDING/TELESCOPING STOCK 1. To adjust the length of pull, depress both (left and right) Stock Extension Buttons and slide stock forward or back. 2.
IMMEDIATE ACTIONS — IN CASE OF TROUBLE! IF YOUR FIREARM STOPS FIRING: Perform the following IMMEDIATE ACTIONS… Remember the word “SPORTS” 1. S lap up on the Magazine to ensure a good lock up in the Lower Receiver. 2. P ull the Charging Handle all the way back and hold. 3. O bserve the ejection of the Case or Cartridge, check Chamber for any obstruction. 4. Release the Charging Handle and let the Bolt spring forward. 5. Tap the Charging Handle to assist the Bolt forward to ensure the Bolt is locked. 6.
REMEDIAL ACTIONS… WARNING: IF YOUR FIREARM STOPS FIRING WITH A LIVE ROUND IN THE CHAMBER OF A HOT BARREL, REMOVE THE ROUND IMMEDIATELY. However, if you cannot remove it within 10 seconds, remove the Magazine and wait 15 minutes with the Firearm pointing in a safe direction (always check that the “SAFE” direction remains safe during that time). This way you and those around you won’t get hurt by the possibility of a round “cooking off”. KEEP YOUR FACE AWAY FROM THE EJECTION PORT WHILE CLEARING A HOT CHAMBER.
BULLET STUCK IN THE BORE… WARNING: IF AN AUDIBLE “POP” OR REDUCED RECOIL IS EXPERIENCED DURING FIRING, IMMEDIATELY CEASE FIRE: Then, 1. Remove the Magazine. 2. Lock the Bolt to the rear. 3. Place the Selector Lever on SAFE. 4. Visually inspect and/or insert a Cleaning Rod into the Bore to ensure there is not a Bullet stuck in the Bore. DO NOT APPLY THE “IMMEDIATE ACTIONS” DESCRIBED ON PREVIOUS PAGES. IF A BULLET IS STUCK IN THE BARREL OF THE FIREARM, DO NOT TRY TO REMOVE IT.
BACK UP SIGHTS The Front Sight Post is threaded - allowing it to be moved up or down for Elevation Adjustments when “Zeroing” the Rear Sight (see “Zeroing Your Sights” on next page). Once the Rear Sight is Zeroed, the Front Sight Post should not be moved. REAR BACK UP SIGHT The Rear Back Up Sight features two apertures and when not used can be folded down flat. To return to the up position press either the side tabs.
ZEROING YOUR SIGHTS… Follow the steps below to establish a Zero at 25 meters. Your MBUS Type Rifle Sights will then be set with a 300-meter battlesight zero. With this procedure, only the Front Sight Post and Rear Sight Windage Knob are adjusted so that you can hit your Point of Aim at 300 meters. 25 METER ZEROING PROCEDURES… 1. Place an appropriate 25 Meter Paper Sighting Target 25 meters downrange and follow the steps below to establish a “battlesight” zero.
ZEROING YOUR SIGHTS… (cont’d.) 5. If you need to raise your next shot group to get closer to the bullseye, rotate the Front Sight Post clockwise one click. A Front Sight Adjustment Tool (Part# RAY-005 - see Bushmaster Catalog or Website) is recommended for this but not necessary – the sight can be adjusted with the tip of a Bullet as shown at right. One click will move the bullet strike point one vertical square on the target sheet. Elevation Adjustment Table a. Sight Radius: 14.1 in. b.
DISASSEMBLING YOUR FIREARM… 1. CLEAR YOUR FIREARM! (as described on Page 6). Disconnect the Sling for convenience. 2. Push the Rear Takedown Pin (a Bullet Tip can help) as far as it will go. Pivot Upper Receiver from Lower Receiver. 3. Push in Pivot Pin (a Bullet Tip can help). 4. Separate Upper and Lower Receivers. 5. Push the Charging Handle fully forward to disconnect the Actuator from the Bolt Carrier. Remove Bolt Carrier to the rear.
DISASSEMBLING YOUR FIREARM… (cont’d.) 6. Remove the Action Spring Assembly from the Bolt Carrier by pressing inward (toward front of the Bolt) and twisting counter-clockwise until the slots on the carrier are in-line with the prongs on the front of the Action Spring Assembly Guide and then remove the Action Spring Assembly. 7. Remove Firing Pin Retaining Pin. A Bullet Tip can help push it out of the Bolt Carrier. 22 8. Remove Firing Pin and Firing Pin Spring out of rear of Bolt Carrier.
DISASSEMBLING YOUR FIREARM… (cont’d.) 9. Remove Cam Pin by turning Bolt Carrier on the side and tapping opposite side of Bolt Carrier. Cam Pin should fall out. 10. Remove Bolt Assembly from Bolt Carrier by pulling straight out. DISASSEMBLE USING STEPS 11 AND 12 ONLY WHEN DIRTY OR DAMAGED 11. Remove Extractor Pin by pushing out with a punch or the tip of a Bullet. 12. Remove Extractor with Spring. NOTE: Press rear of Extractor to check Spring function.
DISASSEMBLING YOUR FIREARM… (cont’d.) REMOVING THE BARREL ASSEMBLY 1. Pull Charging Handle and lock to the rear. 2. Remove Hand Guard by pushing the Hand Guard Retaining Pin through as far as it will go and slide the Hand Guard forward. 4. With the Barrel Plunger depressed, turn the Barrel Locking Lever. counter-clockwise until it stops. 24 3. Lower the Barrel Locking Lever and depress the Barrel Plunger. 5. Pull the Barrel Assembly forward until it releases from the Trunnion.
DISASSEMBLING YOUR FIREARM… (cont’d.) DISASSEMBLING THE GAS PISTON SYSTEM 1. Depress Regulator Plunger and rotate until it is facing toward the barrel. 2. Pull Gas Regulator straight out to remove. 3. Remove Piston Rod and Piston Spring through the front of the Gas Block. NOTE: The Gas Piston System can be disassembled with the Barrel attached or removed from the Upper Receiver. BUSHMASTER DOES NOT RECOMMEND ANY FURTHER DISASSEMBLY. ANY FURTHER DISASSEMBLY MUST BE PERFORMED BY A QUALIFIED GUNSMITH.
INSPECTION — CLEANING — LUBRICATION… AFTER FIRING YOUR FIREARM, clean it as soon as possible to make the job easier and to avoid allowing the development of any corrosion. When your Firearm has not been fired you should clean it at least once or twice a year if you live in a temperate climate, or as often as once a week in a tropical climate. If you get your Firearm wet, clean it as soon as possible to avoid the onset of corrosion or rust.
DETAILED CLEANING TECHNIQUES… NOTE: The procedures below describe cleaning with a standard military issue type multi-piece rod cleaning kit. Other commercial cleaning kits may include alternate cleaning instructions which may be just as effective. CLEANING THE BORE: The bore of your ACR rifle has Lands and Grooves called rifling. Rifling makes the bullet spin very fast as it moves down the Bore and down range. It is difficult to push a new, stiff Bore Brush through the Bore.
DETAILED CLEANING TECHNIQUES… (cont’d.) 4. Remove Patch Holder and attach Bore Brush (leaving it two turns short of tight). 5. Pull the Brush through the Bore and out the Muzzle. You should be able to see the Rod twisting as you pull it - this is the Brush “tracking” in the rifling. NEVER reverse the direction of the Bore Brush while it is in the Bore. 6. After one pull, take off the handle section and repeat the process.
CLEANING THE UPPER RECEIVER… 1. Using a “CLP“ type product, clean all areas (inside and out) of Powder Fouling, Corrosion and Dirt. Never use a wire brush or any type of abrasive to clean the Aluminum Upper Receiver or Bearing Rails - you’ll scratch and damage the finish. A Toothbrush is good for loosening any dirt buildup, and won’t scratch the Receiver. 2. Wipe all components clean and dry, and inspect for excessive wear, corrosion or mechanical damage.
CLEANING THE UPPER RECEIVER… (cont’d.) CLEANING THE BOLT, BOLT CARRIER & COMPONENTS… CHECK THE EXTRACTOR AND EXTRACTOR SPRING: If the Extractor is chipped, or has broken edges in the area of the lip that engages the cartridge rim, it should be replaced. Check that the rubber insert is inside the Extractor Spring. Clean off any Carbon buildup or powder residue. CLEANING/LUBRICATING THE EJECTOR… NOTE: The design of the Ejector makes its disassembly for cleaning somewhat impractical (i.e.
CLEANING THE LOWER RECEIVER… 1. Clean all areas of Powder Fouling, Corrosion, Dirt and Rust. Again, never use a wire brush or any type of abrasive to clean the proprietary composite polymer Lower Receiver. 2. Stocks may require cleaning as necessary and should be cleaned with mild detergent and water. Dry stock or let air dry after it has been cleaned. REASSEMBLING YOUR FIREARM… 1. Insert Piston Rod and Piston Spring through Gas Block and Piston Rod through Guide Block. 2.
REASSEMBLING YOUR FIREARM… (cont’d.) 4. Guide the Barrel Lock Handle to the right until it engages with the Trunnion. Once seated into the Trunnion, turn the barrel locking lever clockwise until there is a positive stop (you may have to depress the Barrel Plunger to start rotation). The Barrel Locking Ring will make audible clicks as the torque is being applied for proper installation. 5. Install Hand Guard over the Barrel Assembly and push Hand Guard Retaining Pin closed to lock into place.
REASSEMBLING YOUR RIFLE… (cont’d.) 6. Insert Bolt into Bolt Carrier. Twist into position so Cam Pin can be inserted (remember Cam Pin can only be installed in Bolt from one side, so if it doesn’t fit right away, twist the Bolt 180° and try again). 7. Once Cam Pin is inserted, align the ridge on the head of the Cam Pin so it is parallel with the Bolt. WARNING: THE CAM PIN MUST BE INSTALLED IN THE BOLT GROUP.
REASSEMBLING YOUR FIREARM… (cont’d.) 10. Insert Action Spring Assembly into the Bolt Carrier by pressing inward (toward front of the Bolt) and twisting clockwise until the tabs on the front of the Action Spring Assembly Guide are in line with the Retaining Slot. NOTE: The Recoil Lug at the back of the Action Spring Assembly should be pointing up toward the top of the Upper Receiver.
REASSEMBLING YOUR FIREARM… (cont’d.) CAUTION: BUSHMASTER DOES NOT RECOMMEND THE PRACTICE OF SWAPPING BOLTS BETWEEN DIFFERENT FIREARMS. DOING SO COULD RESULT IN MALFUNCTION CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR DEATH. 11. Insert Bolt Carrier assembly into the Upper by aligning the notches on the Carrier with the Bearing Rails inside the Upper. Move forward until the locking lugs engage the Trunnion. 12.
MAGAZINE DISASSEMBLY/REASSEMBLY 1. Unload Magazine fully. 2. Turn Magazine base up. Push down and forward on Floorplate with a bullet head or other appropriate device. CAUTION: F loorplate is under pressure, so ensure care upon removal. Always wear eye protection.
MAGAZINE DISASSEMBLY/REASSEMBLY… (cont’d.) 3. Pull gently on Magazine Spring and Follower to separate from Magazine body. 4. Wipe dirt from Body, Magazine Spring and Follower; then lightly lubricate Spring. 5. Orient Follower and Magazine Spring to Magazine Body and carefully insert through bottom of Magazine Body. 6. Slide Floorplate over lip on bottom of Magazine Body and continue sliding Floorplate over tabs until rear of Floorplate catches on Magazine Body.
RE-CONFIGURING THE FIREARM STOCK CHANGE 1. Push the Rear Takedown Pin (a Bullet tip can help) as far as it will go. Pivot Upper Receiver from Lower Receiver. 2. Push the Stock Retaining Pin out. 3. Slide stock upward to separate from lower receiver.
RE-CONFIGURING THE FIREARM (cont’d.) STOCK CHANGE 4. Replace or insert new stock downward into cavity. 5. Push Stock Retaining Pin closed. 6. Pivot Upper Receiver and Lower Receiver together and push Rear Takedown Pin closed. HAND GUARD CHANGE 1. Remove Hand Guard by pushing the Hand Guard Retaining Pin through as far as it will go and slide the Hand Guard forward.
RE-CONFIGURING THE FIREARM (cont’d.) 2. Install alternate Hand Guard over the Barrel Assembly and push Hand Guard Retaining Pin closed to lock into place. CHARGING HANDLE 1. Locate Charging Handle Release Button. 40 2. While using a punch or bullet tip, depress Release Button and slide to the rear while pulling the Charging Handle away from the Upper Receiver.
RE-CONFIGURING THE FIREARM (cont’d.) CHARGING HANDLE 3. Still holding the Release Button to the rear, swap Charging Handle to the opposite side and re-insert or insert alternate Charging Handle. CALIBER CONVERSION 1. Remove Magazine. 2. Unload and clear Firearm. 3. Remove Hand Guard by pushing the Hand Guard Retaining Pin through as far as it will go and slide the Hand Guard forward. 4. Lower the Barrel Locking Lever and depress the Barrel Plunger. 5.
RE-CONFIGURING THE FIREARM (cont’d.) CALIBER CONVERSION 7. Remove the Bolt Carrier and disassemble (See page 22). 8. Select proper bolt head for caliber Firearm is being converted to. 9. Install Bolt into Bolt Carrier. 10. Reassemble Bolt Carrier. 11. Ensure Bolt Carrier is removed from action or is locked to the rear. 12. Select the proper barrel for the caliber rifle is being converted to. 13. Guide the Barrel Extension into the Trunnion. The piston will pass through an opening in the Trunnion. 14.
PROBLEMS/SOLUTIONS… PROBLEM: FIREARM WON’T FIRE Problem: Check For: Firearm won’t fire Selector Lever on SAFE What To Do: Put it on FIRE Improper Assembly Firing Pin Assemble Correctly Retaining Pin Goes In Back Of Large Shoulder On Firing Pin Correct Barrel Installation Remove and Re-Attach Bolt Not Locked In Chamber Tap Forward Assist Too Much Oil In Firing Pin Recess Wipe Out With Pipe Cleaner Defective Ammunition Remove and Discard Too Much Carbon On Firing Pin Or In Firing Pin Recess Cl
PROBLEMS/SOLUTIONS… (cont’d.
PROBLEMS/SOLUTIONS… (cont’d.
PROBLEMS/SOLUTIONS… (cont’d.
PROBLEMS/SOLUTIONS… (cont’d.
MAINTENANCE IN EXTREME WEATHER… EXTREME COLD: Clean and lubricate Firearm in a warm room with Firearm at room temperature. Do not lay a warm Firearm directly on snow or ice. Moving Firearm from cold into warmth will cause condensation which could keep Firearm from functioning. HOT WET CLIMATES: Clean and lube Firearm more frequently in moist climates. Inspect hidden surfaces of Bolt and Carrier Assembly, Upper Receiver, and Chamber/Barrel Extension (Locking Lugs), and Lower Receiver for rust or corrosion.
PARTS AND ACCESSORIES… There are a multitude of ways for the Bushmaster ACR to be upgraded or customized for your specific use. A variety of barrel lengths, profiles, caliber conversion kits, alternate stocks, hand guards, and control parts are available. For a complete listing of replacement parts and accessories please refer to the Bushmaster Parts & Accessories Catalog or go online at www.bushmaster.com/acr.
COMPONENT VARIATIONS… This manual is intended to instruct the Bushmaster ACR Operator in all necessary aspects of Maintenance, Disassembly, Reassembly, Operation and Troubleshooting particular to this firearm. Within the Bushmaster ACR line of products there can be infinite variations of Barrel Length and Type, Stock Type, Lower Receivers, Hand Guards and Sights.
COMPONENT VARIATIONS… The Bushmaster ACR you own, or are using, may vary in appearance from the photographs and illustrations in this Manual, but the concepts, procedures and practices recommended in this Manual are universal to the Bushmaster ACR.
LIMITED ONE YEAR WARRANTY… Bushmaster Firearms are warranted to be free from defects in materials and workmanship. Any such defect of which Bushmaster Firearms International, LLC is given written notice, as provided below, within one year and ten days from the date of first purchase by a customer will be remedied by Bushmaster Firearms International, LLC. This warranty is granted by Bushmaster Firearms International, LLC, P.O. Box 1479, 999 Roosevelt Trail, Windham, ME 04062.
LIMITED ONE YEAR WARRANTY… Under no circumstances shall Bushmaster Firearms International, LLC be responsible for incidental or consequential damages with respect to economic loss or injury to property, whether as a result of express or implied warranty, negligence or otherwise. Some states do not allow the exclusion of limitation of incidental or consequential damages, so the above limitation may not apply to you.
PLEASE PRACTICE SAFE FIREARMS HANDLING! WARNING: IF THIS FIREARM IS CARELESSLY OR IMPROPERLY HANDLED, UNINTENTIONAL DISCHARGE COULD RESULT AND COULD CAUSE PERSONAL INJURY, DEATH, OR DAMAGE TO PROPERTY. CAUTION: CAREFULLY READ THIS INSTRUCTION MANUAL PRIOR TO LOADING AND FIRING THIS FIREARM.
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Bushmaster Firearms International, LLC 999 Roosevelt Trail • P.O. Box 1479 • Windham, ME 04062 www.bushmaster.com For more product information, visit www.bushmaster.com/signin Printed in U.S.A. Bushmaster is a trademark of Bushmaster Firearms International, LLC. Magpul is a trademark of Magpul Industries Corp.
