M4 AEG Keeps Jamming.

Discussion in 'Gun Building, Modifications & Repairs' started by cms416, Aug 27, 2012.

  1. cms416

    cms416 New Member

    20
    0
    Boston
    Hello. As the title states, my G&P M4 keeps jamming. I clear the jam, and i can shoot off a few bb's and it will jam again. I have tried three different hop up units (Two G&P and a G&G) and three different barrels (G&P, G&G, and Matrix), two types of BB's (Javelin and Elite Force), high-cap and mid-cap magazines, even two different outer barrels, yet the problem still persists.

    One of the first instances it jammed was during an Op, and I kept firing the gun to try and clear the jam (not smart). Then my gun wouldn't fire and I opened the gearbox to find my piston in two pieces. I replaced it with a G&G piston I had. I put the gearbox back together and it cycles properly.

    However, the problem still continues. I am honestly at a loss as to why it keeps jamming. I honestly don't think it's the hop-up unit, as I've tried so many and I don't think it's the BB's either. I believe the problem lies in the gearbox. Is it possible the nozzle is not cycling the BB's properly? Should I ship it out to someone to be professionally repaired? I really have no idea what to do. Any help at all would be much appreciated.
     
  2. Mikeinator

    Mikeinator New Member

    345
    0
    Northern VA (no more info, someone might find me...)
    Have you tried using silicone oil or replacing the air nozzle?
     

  3. Mikeinator

    Mikeinator New Member

    345
    0
    Northern VA (no more info, someone might find me...)
    Also, have you made sure that the tappet plate is connected to the air nozzle, that's what allows bbs to cycle.
     
  4. Lefse

    Lefse Well-Known Member Supporting Member

    4,750
    164
    Is the hop-up chamber properly aligned with the gearbox? Are you sure the magazines are feeding well? A good midcap should release 100bb's into the air in less then a second. Are your barrels 100% clean?
     
  5. cms416

    cms416 New Member

    20
    0
    Boston
    Will try replacing the air nozzle, haven't yet.

    The nozzle moves back and forth when I pull the trigger, so for the moment I can safely assume it's connected to the tappet plate. I will double check when I replace the air nozzle though.

    Yup I tried it with multiple mags and they all feed well in other guns. The chamber MAY not be properly aligned, but I think it would be. And yes the barrels are 100% clean.

    Thanks for the help so far guys. I'll update you guys when I replace the nozzle but keep posting for now.
     
  6. Archer627

    Archer627 New Member

    6,174
    5
    Figgington
    You may want to try a Tappet delayer. That may help. When shooting, look down into your hop up chamber and see if it goes all the way back. Also, try it with no hop up on(as in the nub does not protrude into the barrel at all. In essence its off) and make sure your bucking is seated properly. One last thing, is your air seal good?
     
  7. cms416

    cms416 New Member

    20
    0
    Boston
    Hey guys I replaced the nozzle and it worked. It was stiff on the cylinder head causing it to not cycle the BB's properly.