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Would you stake your life, right now, on the condition of your equipment?
NEWS | July 27, 2020

M2 and M2A1 Machine Guns: Not All Parts Are Interchangeable

Soldier firing M2 Machine Gun
Photo by Kevin S. Abel

Although the M2 and M2A1 .50-cal machine guns look alike, they aren’t. So when units swap parts from one model to the other, they risk damaging the weapon and injuring Soldiers.
If your unit has both machine guns, keep the weapons and spare parts separated in the arms room to prevent any mix-ups.
The M2 and M2A1 machine guns have both common and unique parts. For instance, the barrel on the M2A1 has an alignment pin. This pin won’t fit into the M2 barrel support.    
Inspect all M2A1 machine guns to determine if there are any mixed parts installed. Pay close attention to the barrels and receivers. There’s a stamp on the receiver side plate to identify the model, M2 or M2A1.
Operators, here’s how to verify which barrel you have:
  • The M2A1 barrel, NSN 1005-01-541-2478, PN 13027965, has interrupted threads on the receiver side of the barrel, an alignment pin and a barrel carrying handle assembly.
M2A1 Interrupted threads
M2A1 Interrupted threads

M2A1 Alignment pin     M2A1 Barrel support with zig-zag slot
M2A1 Alignment pin                          M2A1 Barrel support with zig-zag slot
  • The M2 barrel, NSN 1005-00-726-6131, PN 7266131, doesn’t have interrupted threads on the receiver side of the barrel, an alignment pin or a barrel carrying handle assembly. But it has a barrel ID tag with the serial number of the receiver.
M2 Uninterrupted threads
M2 Uninterrupted threads 

 M2 Barrel support
M2 Barrel support  

If an M2 barrel is found on an M2A1 weapon, remove it immediately and replace it with the correct barrel. Make sure you follow WP 0008 in TM 9-1005-213-10 (Aug 17).
If you need assistance with your M2 or M2A1 machine gun, contact your local AMC LAR or state surface maintenance manager.

For the full story, check out TACOM GSA 20-022 at:
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