Turning my CQB m4 into a DMR... What should I upgrade?

Discussion in 'Gun Building, Modifications & Repairs' started by guitarmaniak, Aug 5, 2012.

  1. guitarmaniak

    guitarmaniak New Member

    Ok, so I have my G&P M4 just the way I want it for CQB; about 350 FPS at 24 bb/sec. It has a stock G&P inner barrel in it. I did replace the hop up bucking to an X High Tech Bucking. Overall it's pretty accurate for close range.

    Now that I have the CQB set-up, I want to get something with great range that I can use for outdoors games. I scouted out some spring and gas snipers and decided that they weren't really worth the money. That left me with an AEG. I figured that I might as well just get all the internal parts I would need for a DMR and just use my existing gearbox and body. Here's a list of my current internals:

    Classic Army High Speed Gears
    X High Tech 260% Spring
    SHS 15 Metal Half Teeth Piston
    Bravo Aluminum Cylinder Head
    Modify Piston Head (Polycarb)
    Modify Seal Nozzle
    Guarder Tappet
    AMP T5000L Torque Up Motor
    Echo 1 11.1V 25C Lipo

    I'm guessing I could keep the same spring since it should be able to shoot at about 450 fps (Which is where I'd like to keep it), but other than that I'm not sure what I should replace. Please give me actual part names/brands. Don't just say "get high torque gears"... I want reliability and durability out of my build, so keep that in mind.


    Oh, I almost forgot. I have read a few places that V2 gearboxes won't hold up to the pressure of a very powerful spring. Is that something I should be worried about?
    Last edited: Aug 6, 2012
  2. EDI1st

    EDI1st New Member

    Fountain Valley
    Stronger spring, MOSFET, better bucking/barrel.

    Rest are all modifications and tuning.

  3. guitarmaniak

    guitarmaniak New Member

    So the fact that I'm using High Speed gears doesn't really make a difference? Also, from what I've read online my spring should be able to get me up to 450 fps; why would I need to get a more powerful one?
  4. EDI1st

    EDI1st New Member

    Fountain Valley
    Why do high speed gears matter?
    I use high speed gears in my 550fps DMR.
    Instant trigger response.

    People only use high torque gear set because their motors are crap that can't pull anything.

    Well....you are missing 100fps.....so...hm.....big air leak somewhere....
    Last edited: Aug 6, 2012
  5. alex

    alex New Member

    ^^ EDI is correct. fix your airleaks. the higher the fps, the more it will leak. as for high speed vs torque gears, it all depends on your preference. i prefer my battery to last all day (low amp load = torque on torque + 11.1v 25c 1600mAH).

    you also have an option, since it's a cqb build (carbine length), you can just flathop/r-hop it for extended range ~200-230feet at 400 fps (m120) using heavier bbs (.25g should be fine without extending your barrel/cylinder matching). it will have a large spread, but that can be fixed with consistency mods.

    if you prefer the semi-auto route, then you might as well go maximum allowable fps (550).
  6. guitarmaniak

    guitarmaniak New Member

    Before I took it apart this last time I wa shooting at like 425fps. So I wonder what I could have messed up this last time that it's shooting so much lower...
  7. cysko

    cysko New Member

    At the moment I'm in the process of turning my M4 into a DMR but all you really need is a new inner barrel(if you don't have like a 6.03 already) and some better air seals.

    What in doing is extending the barrel by 5in with a barrel extension so I can put in a 495mm 6.03 inner barrel instead of a 380mm inner barrel(my guns a CQB model) which will increase my distance by around half and then also create a better air seal since its a tighter barrel.

    Along with a new piston which allows for a better air seal and more power, turning my 430 fps gun to around 500-530(adding the new/better air seals)
  8. Mystery43_4

    Mystery43_4 New Member

    Santa Barbara

    OP, why the half tooth Piston? You're the 2nd person in 2 days that I've seen using one for absolutely no reason.
  9. EDI1st

    EDI1st New Member

    Fountain Valley
    um......changing piston doesn't add power to the system....
    Only three things create and use power in an AEG....
    Battery...motor and spring...that's it....
    Everything else are just powered by them....

    Increasing barrel length doesn't mean increasing range.....

    TBB for airseal? Derp what?
    Barrel is not suppose to form seal....just FYI.....that's why they are made out of metal...
    Last edited: Aug 9, 2012