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The DPMS LR-308 is a semi-automatic assault rifle based on the military AR-15, but chambered for Winchester .308 ammunition. The evolved design of the LR-308 is classified as an AR-10. AR-10 designs contain proprietary changes that make most of its components non-interchangeable with either the AR-15, or other manufacturer's AR-10s. The standard LR-308 comes with an 18-inch, teflon-coated barrel, and a detachable 19-round magazine. It has a muzzle velocity of 2,600 fps. A Picatinny rail on top of the receiver permits mounting aftermarket scopes or night vision equipment. The rifle is 37.6 inches in overall length, and weighs 9.7 pounds. The manufacturer's recommended procedure requires field-stripping of the LR-308 prior to cleaning.
Items you will need
Verify that the rifle is unloaded. Place bolt in the forward position.
Push in the takedown pin; it is located on the left side of the lower receiver. Pull the pin from the right side until it stops. Swing the lower receiver down and away from the upper receiver.
Push the front pivot-pin in from the left side of the lower receiver. Pull it from the right side until it stops. Remove the lower receiver from the upper receiver.
Pull the charging handle backward until you feel slight resistance. The charging handle falls free of the receiver.
Push the firing pin's retaining-pin out of the bolt carrier; pull it from right to left. The firing pin falls out of the bolt when the bolt is tipped.
Move the bolt forward until it rotates and stops. Turn the bolt cam-pin 90 degrees; remove the cam pin. Separate the bolt from the carrier.
Push in on the buffer with one finger; this holds back the spring tension. Press the buffer retainer; this allows the buffer and spring to move forward. Press the hammer to permit the buffer and spring to travel all the way forward; remove them from the receiver.
Use a punch to push the extractor pin out of the bolt. Remove the extractor spring. Do not detach the spring from the extractor.
Upper And Lower Receiver Cleaning
Clean the bore with a cleaning rod and bore brush wetted with gun-cleaning solvent. Insert the rod from the receiver end of the bore. Don't reverse the direction of the rod while the brush is inserted.
Clean the barrel-locking lugs and the gas tube by hand. Use a worn bore-brush soaked with gun-cleaning solvent.
Clean any areas of the upper receiver that display powder fouling, corrosion, dirt or rust.
Wipe away dirt or grime from the trigger assembly. Use gun-cleaning patches wetted with cleaning solvent.
Clean the inside of the lower-receiver assembly and the buffer with gun-cleaning patches soaked in cleaning solvent.
Bolt Carrier Cleaning
Clean the bolt carrier's inner and outer surfaces with cleaning patches and solvent.
Clean the firing-pin recess and the firing pin. Use a pipecleaner and cleaning solvent to clean the firing-pin hole.
Use a toothbrush and cleaning solvent to scrub carbon deposits and dirt from the bolt-locking lugs. Clean behind the bolt ring, and beneath the extractor lip.
Gus Stephens has written about aviation, automotive and home technology for 15 years. His articles have appeared in major print outlets such as "Popular Mechanics" and "Invention & Technology." Along the way, Gus earned a Bachelor of Arts in communications. If it flies, drives or just sits on your desk and blinks, he's probably fixed it.