| Service Centre |
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| This M4A1 is 2 years old and had seen moderate use. It was put in for a service, as it had begun to double fire sometimes on SEMI AUTO. FIRST INSPECTION: The rear reciever pin was loose, giving a fair indication that the RECIEVER FLANGE had snapped inside (fairly common). It was also apparant that the outer barrel and scope rail were incredibly loose. OPERATION: |
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| Upon field stripping the M4 we found the FLANGE was indeed snapped. This can only be remedied by buying a replacement reciever (M4 or SR16). The motor was removed and it became apparant that the pistol grip had a 2 inch crack in it. The gearbox was removed and fully stripped down and cleaned. It had minimal wear and was therefore regreased (with ABBEY gunbrease) and reassembled. The DOUBLE FIRING problem was diagnosed as a unseated HOP UNIT. The barrel and HOP UNIT were removed and fully cleaned (using silicon oil). The barrel was pretty dirty but had no scoring or erosion. The gun was fully reassembled and test fired. It did not DOUBLE FIRE once on a full 200 rounds on semi auto. Put through the CHRONO it managed a consistant series of shots: |
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| 270,270,270,271,269 FPS (0.20g EXCELL) The M4 was now solid and no longer suffered from creaking or excessive barrel wobble. In the future, the gun requires a new pistol grip (ASAP) and a replacement reciever would be advised for it's next service. |
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| Snapped Flange > |