Manual

7) Remove the gas tube with handguard (Figure 5). Holding the carbine in the left hand at
the fore end, with the right hand and the aid of the drift rotate the gas tube lock upward
about 45 degrees, so that the flat aspect of the pin is vertical; raise the rear portion of the
handguard upward and remove it from the gas chamber socket. Then tilt the gas tube
downward and the gas piston will slide out. 
Note
: In early models of the carbine, the gas tube lock can be rotated without the aid of the drift.
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Figure 5: Removing the gas tube with handguard
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Sequence of Assembly after Partial Disassembly:
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1) Install the gas tube with handguard. Place the gas piston in the gas tube; hold the
carbine in the left hand behind the fore end, and with the right hand insert the front end of
the gas tube into the gas chamber socket. Press the rear portion of the handguard toward
the barrel; rotate the gas tube lock downward to stop. 
2) Join the bolt housing to the bolt carrier (Figure 6). 
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Figure 6: Joining the bolt housing to the bolt carrier
3) Install the bolt in the receiver. Open the magazine cover; holding the carbine in the left
hand! behind the fore end of the stock, rotate it with the right side down; with the right
hand, install the bolt assembly and move it forward; rotate the carbine with the bolt
assembly upward and close the magazine cover. 
4) Install the recoil mechanism in the channel of the bolt carrier, collar end first. 