How to Install an HK USC Barrel
- 1). Remove the magazine from the USC and rack the bolt action back to clear the firing chamber of any live rounds. This should always be your first step whenever you are doing any type of operation on a firearm.
- 2). Locate the barrel roll pin. This is located in the approximate center of the barrel assembly.
- 3). Tap the barrel roll pin from right to left through the USC frame with your punch and hammer. This will allow you to remove the barrel from the barrel assembly.
- 4). Place the new barrel into the assembly and tap the roll pin back into place to secure it down.
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