JG M4 S-System upgrade

Discussion in 'Gun Building, Modifications & Repairs' started by jman79, Aug 9, 2012.

  1. jman79

    jman79 New Member

    100
    0
    memphis
    The S-System has always felt kinda clunky to me whenever it fires, plus it has a terrible hop-up. So i was thinking of modding it, just to a point where it performs well in any situation. So, what are some basic upgrades could i make. I want to keep it pretty cheap, so i don't want a complete gun makeover:p

    Here is kind of an idea of the changes i want:
    350 fps with a 25g BB.
    Better hop-up.
    Feel better in my hands (shim, grease, etc:).

    The gun is currently all stock....

    thanks:)
     
  2. marine121496

    marine121496 Wahahaha~ Supporting Member

    7,506
    2
    Ann Arbor
    ...I would advise changing the hop up bucking to a madbull blue and if you want it shimmed and regreased then just do it yourself. 350 FPS with .25s is about an m120 spring so just put one of those in.
     

  3. Lefse

    Lefse Well-Known Member Supporting Member

    6,226
    1,837
    Start by doing the usual internal tweaks, and if you still feel it's not good enough, you can start replacing parts. Does it have steel bushings? If not, then that's the first thing that should be upgraded. Don't bother ordering parts from Evik or AirsoftGI, order parts from Clandestine Airsoft, WGC Shop or Ehobby Asia, lower prices and better selection.
     
  4. jman79

    jman79 New Member

    100
    0
    memphis
    My main priority is the Hop-up and fps...

    what kind of hop up does the s system have? is it relatively easy to get the bucking off and on????

    i have had some experience shimming and greasing and stuff like that in version 3 gearboxes. I know that m4's have ver. 2's, so how much more difficult is the m4's gearbox, as opposed to ver 3???

    Any advice on type of steel bushing and spring???

    Thanks for the quick reply????
     
  5. Jrod

    Jrod New Member

    334
    1
    Sunnyvale
    Upgrades on a budget:
    Madbull shark tail hop up x2-$10
    Matrix m120-130 spring-$15
    Matrix shims-$4
    Guarder Teflon grease-$6or$8
    Replace all other gb springs-$1
    Upgraded airnozzle-$5
    Smoother out the inside of gb-$0
    Do all this and you should be able to get what your looking for for around $40. ( you're also gonna have to replace the piston to metal teeth eventauly)
     
  6. SilentVectorX

    SilentVectorX Member

    597
    1
    San Angelo
    V2's have a trigger that's easier to assemble,j but the wiring is internal which can possibly be annoying if you try to fit heavier wires... otherwise they are pretty much identical.
     
  7. jman79

    jman79 New Member

    100
    0
    memphis
    I couldn't find the mad bull hop up on clandestine airsoft, but i did find shs buckings. Would she be fine with shs, or should i go with something else? Also, should i just buy a bucking, or and entire new hop up? I don't know anything about hop ups:/

    Thanks
     
  8. TheAirsoftTech

    TheAirsoftTech New Member

    3,510
    9
    Just the bucking, the hopup itself should be fine unless it's cracked. I don't know a whole lot about hopup bucking manufactures and quality, but SHS is usually great.
     
  9. INFANTRYPRO

    INFANTRYPRO New Member

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    You know JG's S-System is already shooting at around 410 with just .2 grams. I'm pretty sure it's like 370-380 with .25's.
     
  10. SilentVectorX

    SilentVectorX Member

    597
    1
    San Angelo
    Yeah, if this is a JG, I wouldn't bother with some things that were listed.

    Hopup unit - leave stock

    Spring - leave stock, probably already a 400 FPS spring anyway. On top of that, I've had a lot of good techs ay that Matrix brand springs are usually vastly mis-rated, so Matrix would be my last choice for a spring upgrade.

    Shims - whatever is cheap, 0.1mm shims are a bonus

    Grease - on gears SuperLube teflon/silicone grease works well, get it from Harbor Freight.

    Air Nozzle - I like Lonex, but they sell out fast.

    Gearbox piston and tappet plate rail polishing - Blue Magic works exceptionally well in my experience, but there's a million ways to polish metal.
     
  11. jman79

    jman79 New Member

    100
    0
    memphis
    Right, but in order to play close quarters, you need it below 350 with 25's. I want to lower the FPS, while maintaining the range and accuracy that is needed for woodland. Of course, that goal is going to be hard to achieve, but i am going to try:p
     
  12. jman79

    jman79 New Member

    100
    0
    memphis
    The hop up is terrible in the s system. No mater what adjustments you make, the bb will not go in a straight line, unlike my CYMA ak. I really don't want to "Fine tune" my hop up (i don't have the necessary tools, confidence, or time), so I'm thinking the next best thing is a complete new hop up:)

    So if i can't get a lonex, should i just go with one of the aluminum ones from clandestine airsoft?

    thanks
     
  13. INFANTRYPRO

    INFANTRYPRO New Member

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    Oh well that's not upgrading that's downgrading the spring. And are you sure it's with .25's? Normally it's with .20's
     
  14. jman79

    jman79 New Member

    100
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    memphis
    yah, 25's:)

    meant "modifying".......
     
  15. INFANTRYPRO

    INFANTRYPRO New Member

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    0
    That's a little odd for them to be doing it by .25's but alright then lol
     
  16. jman79

    jman79 New Member

    100
    0
    memphis
    yah, you can check it out:) it called Mooseherd airsoft, in nashville, tn:)
     
  17. INFANTRYPRO

    INFANTRYPRO New Member

    598
    0
    Oh I used to live in Maryville. I'll be going to college at Maryville university so I'm sure we'll cross paths there someday lol.
     
  18. jman79

    jman79 New Member

    100
    0
    memphis
    Alright...so any opinions on what i should do to improve the hop up? Complete new hop up? bucking? brand?

    what spring type should i use to bring down the hop up to at least 370 fps with .20's?
     
  19. TheAirsoftTech

    TheAirsoftTech New Member

    3,510
    9
    Don't know if this was already mentioned but, get a new bucking, and fine tune it. Systema or madbull buckings are pretty good and are cheap.

    An m110 should put it right around there if your compression is good.
     
  20. jman79

    jman79 New Member

    100
    0
    memphis
    What type of hop up does the S system have?