Kln75's build thread.

Discussion in 'Gun Building, Modifications & Repairs' started by Kln75, Jun 10, 2015.

  1. Kln75

    Kln75 Member

    745
    5
    Melissa
    Hey everybody! Most of you probably haven't seen many of my posts because I basically only lurk but I've decided to come out of the shadows. I have some experience working inside the gearbox but I still have a LOT to learn. This thread is going to help me learn by providing a journal for my etching adventures so you guys can give me all the constructive criticism I know I'll need to be a better tech. So without further ado let's get down to business :D I have always wanted to make a DMR and between summer finally arriving and me being in the financial position to afford a DMR I am ready to start! My goals for this build are
    -Almost instant trigger response
    -To be able to hit a torso sized target at 275 feet 8/10 times
    -Having my FPS between 420 and 430 FPS to meet my fields MED

    Here is my parts list to complete these goals:

    GB shell: Stock JG v2 gearbox shell. This should be fine since I'm not doing anything extreme here.
    http://www.evike.com/products/35432

    Gears: SHS 13:1 gears. These should give me pretty good trigger response and they can handle the spring I'm wanting to put in.
    http://www.evike.com/products/32917/

    Motor: JG blue long version. not much to say about it.
    http://www.evike.com/products/29435/

    Air nozzle: I'm not sure what air nozzle to use so suggestions are welcome.

    Piston head: I'm also unsure of what piston head to use.

    Bearings: I also don't know what bearings i should use.

    Piston: SHS 15t piston
    http://www.clandestineairsoft.com/p...ton-with-15-teeth-shs-blue-15-tooth-p-56.html

    Spring: Prometheus MS120SP spring
    http://www.brillarmory.com/index.php?main_page=product_info&cPath=44_61&products_id=153

    Spring guide: CNC BAAL spring guide
    http://www.evike.com/products/48150

    Cylinder: CNC one piece v2 cylinder and cylinder head
    http://www.evike.com/products/44024

    Tappet Plate: Stock JG v2 tappet plate

    Selector plate: Stock JG m4 selector plate

    Trigger mech: One of Zard's mosfets. Everyone suggests them and seeing as I don't think I'm ready to make my own they seem the clear choice.

    Wiring: 16 gauge wiring should fit in a v2 GB correct?

    Hop up: Lonex m4 hop up chamber. It's been working fine for me so far so I don't see a reason to replace it.
    http://www.evike.com/products/35846/

    Bucking: I've heard Lonex 70d buckings are pretty nice for DMRs although I am currently using a G&G green.
    http://www.evike.com/products/43109/

    Barrel: I have a polished 509mm stock brass barrel I've been using and if I lap it I'm hoping to get nice results. If not I will go the sure way and buy a Prometheus 509mm 6.03 tight bore.

    Battery: I know that I'm going to need a 3s lipo but I'm unsure of what C rating and mah I need. Would this one work?
    http://www.hobbyking.com/hobbyking/...tech_2000mah_3S_15_25C_Lipo_AIRSOFT_Pack.html

    Mods: Compression, AOE, shimming, wiring to deans, R hop (May pay Zard to do this if I can't do it right)

    I think that covers just about everything. If you have any suggestions, constructive criticism or I missed something please speak up and correct me. Thanks guys!
     
    Last edited: Jun 10, 2015
  2. banana

    banana New Member

    48
    0
    I would suggest Guarder SP120 spring, on an M4 platform it should get you to your target FPS and Guarder springs are most consistent which is essential when you are building a DMR.

    I have JG Blue motor paired with SHS 13:1 gears in my AK74 and trigger response is poetry! You will love it! I have 2S 1300mah 25C and get 16RPS on Guarder SP110 spring. 25C and 1300mah gives 32,5A (25*1,3). You want as much amperage as possible. Don't worry, motor will draw only as much as it needs. Still I would not recommend going below 30A.

    I would advise against one piece cylinder. I bought one for my build and decided not to use it. First it is difficult to make a perfect installation of a sorbopad (which you WILL NEED, get a 70D + protective rubber pad - use rubber from inflating bike tube). Second, the finish inside is very rough and would require a lot of sanding and you will never manage to sand it evenly to make it consistant. Get SHS double o-ring cylinder head and SHS full cylinder, sealing will be perfect.

    SHS steel 15t piston is very good, just make sure you correct your AOE (with sorbo and spacers) and glue your rack. I use SHS alu piston heads in my builds. They are light, consistant and durable. Some people prefer POM pistons, but I like to be on a safe side and have it aluminum.

    For mosfet, check GATE mosfets. I have two and love them. They are easy to install, wiring is super simple compared to regular mosfets.

    Also R-hop your barrel and just get a bucking that gives you the beast seal.
     

  3. Kln75

    Kln75 Member

    745
    5
    Melissa
    Thanks for the reply. I chose Prometheus because they have great quality control but if Guarder has the same quality but for a lower price I will definitely look into it. For a battery I found this on HobbyKing and I was wondering if this is a good choice?http://www.hobbyking.com/hobbyking/...tech_2000mah_3S_15_25C_Lipo_AIRSOFT_Pack.html
    How complicated is the gate to install? Do you think it's worth the price?
     
  4. Wingman703

    Wingman703 Moderator Staff Member Moderator

    5,541
    538
    Atlanta
    Ditch shopping at Evike for your parts. You will find better prices and customer service shopping completely at Cland and Brill.

    For the air airnozzle and piston head, Lonex is the option you can't beat. Instead of bearings, go for the more stable bushings.
    For a 'fet, Zardichar's is unbeatable from both the price and quality standpoints.
    The 509 inner may be a smidgen too long, generally its not suggested to go over a 455 if your going to be utilizing heavy BB's, which you should for a DMR.
    The G&G green is an excellent bucking, unless its giving you issues, no need to replace.
    The mods you listed are a good place to start, but for a good DMR, you need to go farther. Barrel stabilization, hopup shimming(may not be needed with the Lonex), proper usage of heavyweight BB's, ect.

    The battery you listed is OK, but bigger is always better. Aiming for more Mah and additional C rateing would be better(but like I said, bigger is always better. Can't go too big when it comes to batteries).
     
    Last edited: Jun 10, 2015
  5. Topper

    Topper Resident Donkey Supporting Member

    2,396
    150
    New Orleans
    AFAIK, the battery is fine, but you need to either
    A) rewire it to XT-60's or XT-T's (deans)
    B) buy a battery that already has XT-60's

    http://www.hobbyking.com/hobbyking/store/__7294__Rhino_2350mAh_3S_11_1v_20C_Lipoly_Pack_.html

    Is probably a better choice. It is only slightly bigger, and has higher mah, slightly cheaper (more if you include the materials to rewire) and is already wired to XT-60's, the obviously superior connector.
    If you're OK with wiring to an external battery bag, http://www.hobbyking.com/hobbyking/store/__7298__Rhino_4900mAh_3S1P_11_1v_20C_Lipoly_Pack.html
    Is a huge battery with decent connectors.

     
    Last edited: Jun 10, 2015
  6. Kln75

    Kln75 Member

    745
    5
    Melissa
    I already ordered the piston for the gun before I considered doing a DMR. Will it still work or should I go ahead and order the Lonex? Tomorrow I can post pictures of my stock to show how much battery space I have and the whole gun if anyone is interested. I'll post an updated parts list in a few days to make sure I've looked at all my options and I've gotten the best I can. I should be able to start ordering parts the week after Father's day. Thanks for the help so far guys!
     
  7. Topper

    Topper Resident Donkey Supporting Member

    2,396
    150
    New Orleans
    The piston is fine, I'm just a Lonex fanboy. If you use a Lonex POM head it should put you at 24.6 grams, so you should be pretty close for that.

    Edit: I should explain this. In a DMR you should be using heavy bb's, around .36-.40 at least. The "best" piston setup weight is approximately 23-24 grams to maximize joule creep.

    Don't be afraid to get drill-y and use an external battery bag, or as I've seen on a couple guns here, tape your battery to your stock. All you need is to drill a hole for the wires in the buffer tube, feed them out, and solder on the connectors. Again, as wing said, bigger is better for batteries. Don't be afraid of the 4900 mah battery.
     
    Last edited: Jun 10, 2015
  8. kozicki

    kozicki New Member

    26
    0
    Permatex Gasket maker comes in handy with compression in DMR builds. Can seal cylinder to cylinder head and bucking to barrel. Just helps get super consistent compression.

    Why not make a frankentorque? I dont know if you're keeping full auto or not. It will give you fast trigger response.
     
  9. Kln75

    Kln75 Member

    745
    5
    Melissa

    My field allows full auto at 450 with a MED of 50ft so I'm planning on keeping full auto.
     
  10. Topper

    Topper Resident Donkey Supporting Member

    2,396
    150
    New Orleans
    Meh, if it's full auto it's not really a DMR, but whatever your field allows.
     
  11. Kln75

    Kln75 Member

    745
    5
    Melissa

    I would prefer to avoid using an external battery because to me it kills the aesthetics of the gun. I took pictures of my stock so you guys can see roughly how big of a battery I can fit. Sorry for the potato pics but they where the best I could do.
    [​IMG][​IMG]
     
  12. Topper

    Topper Resident Donkey Supporting Member

    2,396
    150
    New Orleans
    Can you give us dimensions in mm? Then we can tell you for sure. Also, you could rewire it to the front and use a PEQ box, if you like that look.
     
  13. banana

    banana New Member

    48
    0
    It is so easy you could teach a monkey to install it. Two wires go straight to motor and with mosfet you get a thin double signal wire which goes to the contacts. See the example on my AK. I prefer GATE over anything else, since they are connected to your wiring with deans and can be quickly interchangable between more guns.

    [​IMG]
     
  14. Kln75

    Kln75 Member

    745
    5
    Melissa
    The battery space is 25mm X 25mm X 180mm. I would be open to wiring it to the front since I already plan on buying a PEQ for the looks.
     
  15. kozicki

    kozicki New Member

    26
    0

    Doesn't the GATE not protect trigger contacts since it's not actually hardwired in? And it also has active breaking, just unnecessary strain on the motor. You can prevent overspin mechanically.

    Just wondering because a gun I recently bought has this in it.
     
  16. Wingman703

    Wingman703 Moderator Staff Member Moderator

    5,541
    538
    Atlanta
    Gates are hardwired, however, they are not great 'fets. High failure rate from what I have heard.
     
  17. Rushin

    Rushin Well-Known Member

    3,920
    32
    Kalamazoo

    Woah, so plug-and-play fets don't actually protect trigger contacts? I've seriously been misinformed... What's the point of them then?
     
  18. CrusaderAirsoft

    CrusaderAirsoft Member

    802
    17
    Winchester
    Pretty much burst function, and also tricking newbs into thinking their guns are uber "lipo ready" now. :rolleyes:
     
  19. Rushin

    Rushin Well-Known Member

    3,920
    32
    Kalamazoo

    Dang, I thought I could get around my F2000's terrible wiring system... I'm thinking of finding a way to put some G&P M4 trigger contacts in there so I have an easier time wiring it...
     
  20. Lefse

    Lefse Well-Known Member Supporting Member

    6,226
    1,837
    Looks like that GATE 'fet is wired to protect the trigger contacts if you ask me. Why would it have a separate set of trigger wires if it wasn't designed to protect the trigger contacts? The F2000 platform has similar wiring setup as AUG's and P90's right? In that case you simply connect the gate wires to the secondary trigger switch. The old positive motor wires becomes the signal wire for the mosfet, and you route a new positive wire to the motor directly from the battery connector.

    I respectievly disagree with going with the Lonex "red" piston over the SHS/DA 15T piston, I've gotten much better results with latter. Lonex pistons barely last a season in my builds, and I have easily stripped several. So far I haven't worn out any of my DA/SHS 15T pistons, and haven't been able to break any of them, after twice as many cycles as I put through my Lonex pistons. I've ran them in setups that would have stripped Lonex pistons from the sheer stress.