Help needed

[Filipp14]

Hey guys, last saturday I played an airsoft skirmish with an echo 1, aks-74u, and after shooting about 100 rounds it would not shoot in automatic, i mean it would shoot, but bb's would never come out, except on semi only. Does anyone have any idea on what might be the problem?

[Falcon7]

Maybe the tappet plate is not going back far enough and feeding the bbs? Turn the gun over and look inside the hop up unit while firing to see if it's moving all they way back.