D boys scar DMR

Discussion in 'Gun Building, Modifications & Repairs' started by dodger0729, Sep 6, 2012.

  1. dodger0729

    dodger0729 New Member

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    I want to upgrade my D boys Scar L. Unfortunately I'm new to gun building and I've taken the gearbox apart cleaned and regreased it. I have 200-300 dollar price limit. This will be something I do over time and would like to know what I should upgrade first. My fps limit is 400 and i would like to keep it hitting that hard. I also would loke a lot of accuracy. I don't care about rof.
     
    Last edited: Sep 6, 2012
  2. Blades

    Blades New Member

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    First of all, a DMR is semi-auto only, so you can either choose a real DMR or long-range AEG. A good barrel (Prometheus for great performance, Madbull for good performance), new hopup bucking (Madbull has worked fine for me). That and a new all metal hopup chamber would suit you well as far as accuracy upgrades go. Don't have any suggestions on the hopup chamber though, do some more research on that.
     

  3. dodger0729

    dodger0729 New Member

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    So I shouldn't do anything to the gearbox or get a new piston, spring, etc.? It is hitting consistently at four hundred fps with stock parts but I don't trust them for some reason.
     
  4. ShooterMcgavin

    ShooterMcgavin New Member

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    New Port News
    Well look at the stickies in this section they give you an idea of what you should be looking for when upgrading. The Scar isnt really meant to be a DMR. Though you can make it into one but it will take time, TLC, and money, all of which you have. I would recommend instead to make a very accurate gun that isnt specifically a dmr that has good range, trigger response, and good ROF. Again the stickies in this section explain how to do alot of this.
     
  5. dodger0729

    dodger0729 New Member

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    So a high rate of fire and accuracy? Can that be achieved? The field I play at is really open and the farther I can hit someone the better. I had a bolt action fully upgraded but I wanted to be more effective and didn't have the patience.
     
    Last edited: Sep 7, 2012
  6. Lefse

    Lefse Well-Known Member Supporting Member

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    Read through that DMR thread, then you forget that old mantra about what guns can be DMR's and not, there is nothing against using a SCAR AEG as a DMR, you just gotta tune it properly. The stock hop-up chamber is fine, just make the hop-up arm 100% stable, I think hop-up shimming should be mentioned in that DMR thread, if not you can google it. An R-hop is the hop-up system of choice for a DMR, look into that. Consistent FPS is important, you also want all the components in your gun to be 100% stable to give tighter groupings. Good trigger response is also good, look into a high torque neo motor if it doesn't have one already. Electrical upgrades should be the usual "li-po upgrade", low resistance wiring, deans connectors mosfet, etc.

    Yes, high ROF and accuracy can be combined, but will require a significant amount of work hours and patience. Your budget is more than enough, accuracy is more about tuning that parts really, but high quality parts will make it easier to achieve good results, of course. Have you done the usual reliability mods to the gearbox? That's where you should start, reliability should be first priority, a dead gun is useless no matter how accurate it is.
     
  7. dodger0729

    dodger0729 New Member

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    Are there any brands I should avoid before I start?
     
  8. Lefse

    Lefse Well-Known Member Supporting Member

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    Avoid Systema, most of their products are overprised junk. I prefer Lonex and SHS for internal upgrades myself. Guarder has some good stuff too.
     
  9. dodger0729

    dodger0729 New Member

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    Thanks guys I will keep it updated with every step. Just in case I have problems
     
  10. Lefse

    Lefse Well-Known Member Supporting Member

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    Sounds like a plan. :)
     
  11. dodger0729

    dodger0729 New Member

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    So I decided to start with the gearbox instead of anything else. I bought a shs 15 tooth blue piston, shs 7mm steel bushings, shs shims, 16:1 shs gear set with gen 1 bushel, lonex plastic POM ball bearing piston head, a scatterplot sorbopad 3/16 thick 70 duro, a lonex m110 spring, and finally a guarded custom standard motor long type. I want to move on to the hop up but want to start with a tightbore. I just need a suggestion for length I want to keep the barrel extension and a suppressor. So I can put in a longer inner barrel. How long do you guys think I should go?
     
  12. Retrospection

    Retrospection New Member

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    Kimballton
    I got a 285mm Prometheus in my scar. However it sticks out like 5mm. But I have the barrel extension so it is completely hidden. With barrel extension on your looking at 300mm. Add a 100-150mm suppressor and you'll have your 400mm long range type barrel.
     
  13. dodger0729

    dodger0729 New Member

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    Ok so now I want to dive into changing out the hop up and possibly getting into air sealing what do you guys think I should do?
     
  14. S0m3_0n3

    S0m3_0n3 New Member

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    I think you should read the stickies :p as for the hop up, most don't need the unit to be changed, just a new bucking/nub a good thing to look into is hs5's r-hop
     
  15. dodger0729

    dodger0729 New Member

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    I'm having trouble. I don't know how many teeth to dremel off and I just finished reshimming. Can some one tell me how much I need to dremel off?
    image-3144460248.jpg
     
  16. S0m3_0n3

    S0m3_0n3 New Member

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    the entire second tooth, usually some of the third, I believe you want to shave it down until the first tooth on the sector can pass and make contact with the pickup tooth on the piston
     
  17. Lefse

    Lefse Well-Known Member Supporting Member

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    If the piston is fully forward in that photo, then your AOE is incorrect, it's too far back, and you remove as much as necessary of the teeth.
     
  18. dodger0729

    dodger0729 New Member

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    I put a sorbo pad in and that's as far in as the piston goes. I need it to touch the first tooth correct? Then I'll take off about three teeth
     
  19. Lefse

    Lefse Well-Known Member Supporting Member

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    Then the sorbo pad is too thick. The surface of the first sector tooth and the piston pickup tooth should be parallel, which they are not in your case. That's what I like about using rubber from bicycle tubes, it gives more adjustability, I just add layers until the AOE is optimal, usually it takes 4 layers.