Figure 13-35 shows the major component groups and assemblies of the .50-caliber BMG. For routine cleaning and maintenance, you need to know the general disassembly procedures. Detailed disassembly procedures remove all parts from each group. These steps are explained in the FM23-65 of the U.S. Army. Be sure to consult the field manual if you must do a detailed disassembly.

Before starting general disassembly procedures, you must clear the weapon. This includes ensuring the gun is unloaded, cocked, and the bolt is forward. The primary steps involve removal of the following parts:

1. Barrel group

2. Backplate assembly

3. Driving spring rod assembly

4. Bolt stud

5. Bolt group

6. Buffer body and barrel extension groups

7. Buffer assembly

Remove Barrel Group

The actions required to remove the barrel group are shown in figure 13-36. Turn the cover latch lever forward and raise the cover group (view A). Pull the retracting slide (bolt) handle to the rear slowly (view B). That moves the recoiling parts of the gun to the rear. Pull rearward until the lug on the barrel locking spring aligns with a 3/8-inch hole. The hole is in the right sideplate of the receiver, just below the feedway exit. The barrel can be turned only when the lug is aligned with the 3/8-inch hole. Place the smallest loop of a .50-caliber belt link (or suitable spacer) between the trunnion block and the barrel extension. This holds the barrel locking spring lug in alignment with the 3/8-inch hole in the right sideplate (view C).

Now, unscrew the barrel from the receiver (view D). Be careful not to damage the threads or barrel-locking notches when setting the barrel down. Complete this phase of disassembly by pulling back slightly on the retracting slide handle. Then remove the .50-caliber link (or spacer) from the receiver. Do not allow the bolt to slam forward with the barrel removed; this causes damage. Let the retracting slide handle (and bolt) ease forward carefully.

Figure 13-36.-Removing the barrel group.

Figure 13-37.-Removing the backplate assembly.