Help a fellow Belgrim (AUG thread)

Discussion in 'Gun Building, Modifications & Repairs' started by Belgrim, Feb 22, 2019.

  1. Belgrim

    Belgrim Member

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    Hey there guys. I am new to airsoft and I have bought a JG AUG. I knew that it is a bad gun for a beginner but it is my favourite weapon and i wanted it so bad.

    Anyway, from the first time I got it it started behaving a little weird. Let me explain.
    Even before using the gun for a match, I bought a LiPo battery (7.4) for the gun and changed the tamiya connectors to deans.

    I went to my first match and it was a little cold (around 0 to 5 degrees C). The hop up started under performing and even was double feeding some of the time or not feeding at all. The hop up was only performing well when i used full-auto, slowly gaining maximum range with each shot, but after a while (of not shooting) it would under perform again.
    Some guy at the field told me that it was because of the cold. Some other guy mentioned that it might be a piston or cylinder problem, or a cylcling problem.

    I disassembled and reassembled the hop up and at the next match the same thing was happening except the feeding problems which were corrected for some reason. I knew those guns have a hop up problem from the get go so I purchased a Lonex aug metal hop up and a new plastic nozzle with an O-ring inside it, plus a metallic cylinder head with double O-ring (even though the stock one seemed OK) and replaced the stock ones. Also I shimmed the gears and now I use a maple leaf bucking and nub.

    I went today to test the gun for a few rounds and the shots were not going very far. After i increased the hop up the shots went even shorter and with very low speed. I even replaced the stock barrel with a new guarder one (both are 509mm) but nothing has improved.

    Anyone has any idea what is exactly happening with the gun? I will keed you updated with more info. I will probably test the gun again in 2 days.
     
  2. Honeybadgerz17

    Honeybadgerz17 Well-Known Member

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    Did you check your compression after all the parts you threw into the gun were installed
     
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  3. Belgrim

    Belgrim Member

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    How do I check the compression? I checked the gears after I shimmed and they looked fine and the Piston was cycling pretty good.
    I checked for any cylinder leakage but there was none.
     
  4. Lefse

    Lefse Well-Known Member Supporting Member

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    AUG's have hop-up issues? That's new information for me. I know they are more susceptible to feeding issues, but the hop-up itself has performed well in all of my AUG's. One thing I've found is that aftermarket chambers don't necessarily work well, I had to put the stock chamber back in my JG AUG.

    I'm guessing your issues were caused by the cold, regular hop-up rubbers are more affected by cold. You could install one made of silicone or softer rubber to compensate. I presume you have cleaned the barrel? It's also possible that the Maple Leaf hop-up rubber isn't compatible with the current barrel, I have had issues with them with barrel with Krytac type hop-up window.
     
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  5. Belgrim

    Belgrim Member

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    Hmm that one i didnt think of. So now i should buy a top class promethius barrel or something with a particular type of window?
     
  6. Lefse

    Lefse Well-Known Member Supporting Member

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    Or just test with a regular hop-up rubber instead. It's also possible to elongate the hop-up window with a file if you're comfortable with doing such modifications.
     
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  7. Belgrim

    Belgrim Member

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    If i post an image of the barrel window, will you be able to recognize if it is the right window type?

    Also there is a chance that i might have put a little silicon oil inside the bucking, but that does not explain why with more hop up the BBs go even shorter range. I will clean it then and try again tomorrow on the field
     
  8. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Stop throwing parts at it.

    These things are systems and parts are NOT all interchangeable.

    Work one issue at a time. Half of the parts you bought were "NOT" upgrades.

    You most likely just need a soft hop-up packing (also known incorrectly as a "bucking").

    What degree ML packing did you buy?
     
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  9. Belgrim

    Belgrim Member

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    I bought the 70o one, but it is much softer that the stock one. Also i just noticed that the ring on the barrel that is supposed to be inside the hop up is not fully inside the hop up.
    I tried pushing it inside but I just cant get it. I dont know if that is a problem, if it is then i can swap the stock barrel in again see what happens.[​IMG]
     
  10. Lefse

    Lefse Well-Known Member Supporting Member

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    I installed the same Lonex hop-up unit in my AUG, but had to put the stock one back in, as I got severe feeding issues with the Lonex unit. I suspect that both JG and CA have slightly different specs than TM on their AUG's, so the Lonex chamber probably only fit properly in a TM AUG. That being said I don't see why on would want to replace a TM hop-up unit.
     
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  11. Belgrim

    Belgrim Member

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    UPDATE:
    I cleaned the hop up with a towel and reinstalled it.
    I tested it on the field today and I was blown away, the range of the gun was 1.5 times the stock range and the consistency improved.

    The only thing that I noticed is that even though the consistency improved, the bbs would fly a little to the right at the end of their trajectory.
    I guess it must be the packing again? Maybe I installed it a little sideways and now the BBs fly a little to the right? It was a bit windy today though.

    Anyway thanks for helping me and I will keep you updated. For some reason I feel this isn't the last time that I will face problems.
    (Excuse me for my grammatical errors, English is not my first language).

    Edit: btw the gun only double fed once at the start and never again, so I guess lonex hop up chamber may actually be good for JG AUG?

    Edit+: I also forgot to mention that I duct taped the barrel ring to the hop up, so now I probably have a better hop up seal?
     
  12. Honeybadgerz17

    Honeybadgerz17 Well-Known Member

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    Make sure your barrel isn't rotated in the hopup, since the hopup packing is connected to that
     
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  13. Belgrim

    Belgrim Member

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    I dont know if I should create a new thread for this:

    I want to install a 120 m/s spring in my AUG and i want to ask if it can handle it? Can my stock gears and piston handle a 120m/s spring. The stock one is 100m/s

    Also I usually use .25g BBs and I want to use .28g in the future but not higher. How can I have maximum efficiency? I intend to use the 509mm barrel and not anything shorter or longer. What is the best cylinder volume, piston weight and whatever else to have the best setup, all these with the 120m/s spring and .28g BBs?

    I remember seeing around a chart on this forums with the best barrel lenghts to cylinder volume ratios for every BB weight. Any ideas?
     
  14. Honeybadgerz17

    Honeybadgerz17 Well-Known Member

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    Yes you should've made your own post. But look at this thread https://www.airsoftsociety.com/threads/what-barrel-length-goes-with-what-bb-weight-in-an-aeg.153191/
     
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  15. Belgrim

    Belgrim Member

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  16. -Spitfire-

    -Spitfire- Well-Known Member Supporting Member

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    Stock spring is an m120 to my knowledge, as it's a JG. For heavy BBs, you'll need a full cylinder and, if possible, a shorter barrel than you have now... Though being slightly undervolumed isn't a bad thing.

    Yup, likely installed the barrel slightly off-center... Try double-checking it by looking down the barrel while it's installed in the hopup to ensure that the number appears centered, relative to the hopup. And if you haven't already, clean your barrel with rubbing alcohol... Likely has grime in it from the factory. Also, try testing the accuracy with heavier BBs, when it's not windy.

    Prommy is below top class. Lambda, PDI, and EdGI steel are your main top of the line options.
     
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  17. Belgrim

    Belgrim Member

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    oh really? I thought it was 100 m/s because it is supposed to shoot around 340fps. I havent chronoed it to be honest though.
     
  18. Honeybadgerz17

    Honeybadgerz17 Well-Known Member

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    ......it was a long day yesterday:confused:......
     
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  19. -Spitfire-

    -Spitfire- Well-Known Member Supporting Member

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    There's a lot more that goes into an individual gun's fps than just the spring rating.... Compression, piston weight, BB weight, bore quality, bore diameter, barrel length, cylinder porting, cylinder ID...
     
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  20. Belgrim

    Belgrim Member

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    cylinder ID?