Headspace and timing on the M2A1 is fixed and not adjustable by the operator and must be verified by field maintenance at time of issue. Improper headspace and timing can cause malfunctions (internal explosion) and damage to the gun. Flying shrapnel may cause injury to personnel.
Be sure to clear weapon before disassembling, cleaning, inspecting, transporting, or storing. Clearing consists of unloading the machine gun and visually inspecting weapon and chamber to ensure all rounds have been removed. Do not release the bolt or press the trigger. Ensure weapon is cleared and on SAFE mode.
Never open the cover on a hot weapon or when performing immediate action. An open cover cook-off could explode and result in serious injury or death. Keep the weapon pointed down range while performing immediate action. A cook-off can occur within 50 rounds when the weapon and ammunition have been sitting in the sun.
- Use only ammunition authorized for use in the M2A1 Machine Gun.
- Do not expose ammunition to the direct rays of the sun.
- Do not oil or grease ammunition. Oiled cartridges will produce excessive chamber pressure.
- Depending on climate conditions, do not leave live rounds laying on top of hot expended brass.
- Round may fall to surface and possibly explode.
Warning Summary
This warning summary contains general safety warnings and hazardous materials warnings that must be understood and applied during operation and maintenance of this equipment. Failure to observe these precautions could result in serious injury or death to personnel.
First Aid
For first aid information, refer to FM 4-25.11. Air Force personnel should refer to AFMAN 44-163(I). Marine Corps personnel refer to MCRP 3-02G.
Safety Warning Icons
FLYING PROJECTILE – Spring-loaded parts could release and hit body causing injury or death.
EAR PROTECTION – Noise level will harm ears. All soldiers within 56 metres of the firing position should wear single hearing protection, adequate for up to 1,000 rounds within a 24-hour period.
EXPLOSION – Material may explode if subjected to high temperatures, sources of ignition, or high pressure.
EYE PROTECTION – Material will injure eyes. Wear appropriate eye and hearing protection when repairing, firing, or cleaning the weapon.
WEAPON FIRE – Accidental discharge could penetrate the body causing serious injury or death.
HOT AREA – Part is hot and can burn. Allow barrel to cool before changing if the carrying handle is broken; use mittens if handle is not present.
General Safety Warnings
During barrel installation, the charging handle must be pulled back to view the square on the barrel locking lug through the 3/8 in. hole in the right side of the receiver. If the square on the barrel extension is NOT pulled back PAST the 3/8 in. hole, the barrel will not be properly attached. Failure to comply may cause an explosion.
Never attempt to cock the machine gun with the back-plate removed and the driving spring rod assembly in place. The retaining pin could slip from its seat in the side-plate and cause serious injuries to anyone behind the weapon.
Do not attempt to release the firing pin with cocking lever forward. The cocking lever could spring back forcibly and cause serious injury to the hand.
Use only ammunition authorized for use in the M2A1 Machine Gun. Do not expose ammunition to direct rays of the sun. Do not oil or grease ammunition — oiled cartridges will produce excessive chamber pressure.
Do not use a damaged barrel. Inspect barrel for damaged threads and guide pins before installation.