How to Get The Best Performance Out of The KWA LM4 GBBR

Discussion in 'Gun Building, Modifications & Repairs' started by chuck123, Nov 15, 2015.

  1. chuck123

    chuck123 New Member

    Please close thread.

    Please close thread.
    Last edited: Nov 19, 2015
  2. Raven1st

    Raven1st Well-Known Member

    San Ramon valley
    Polish your stock barrel.

    Use decent heavy BB's. BBBastard and G&G are good. Goldenball has given me feeding issues in all 3 of my GBBRs so I have reservations recommending them.

    Swap out the stock bucking. 5 out of 6 times an aftermarket bucking is far better, and add an Rhop if you really want range.

    Seal/shim everything (bucking, mags, router, nozzle).

    Get an NPAS. It's sooo helpful.

    Dropping in a steel trigger set will prevent all future trigger issues.
    Anything that is not steel/aluminum in a GBBR will fail at some point, so steel up when you can. Start with the trigger, then get a mill-spec buffer tube, then anything else that tickles your fancy.

  3. Raven1st

    Raven1st Well-Known Member

    San Ramon valley
    The majority of my knowledge lies with WE GBBR'S, but the same basic things can be applied to both brands.

    RA Tech makes decent trigger sets. Sometimes they have fitment issues, but those are easy to fix and the triggers are worth it.

    Barrel can be kept stock if you polish or lapp it.
    From what I have seen guys like the Evo hopup unit far better than the stock one.

    A decent bucking (Maple Leaf) and nub (best to make one from eraser) paired with a good hopup unit can get you good results, but a properly tuned Rhop will always be better.

    Replacing the stock Orings and RTV sealing all seals are other good things to do. Those will help with gas efficiency and prevent leaks.

    One other thing I have done before is to use very fine (2k+) sandpaper and finish off all the areas that have signs of wear. This helps smooth out the action a little bit.