Broken Free [ArmaLite M15a4 Carbine] - CA-SP001P-1

Discussion in 'Gun Building, Modifications & Repairs' started by Rainmaker, May 11, 2018.

  1. Rainmaker

    Rainmaker New Member

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    3
    PDX
    My friend got tired of his CA M15a4 Sportline. Correction, my friend abused a CA M15a4 by not lubing it properly, allowing the barrel to stay dirty and not understanding to not cycle the gearbox when it jams. It had been in the shop, possibly multiple times.

    IMG_20180425_215234812_edit.jpg

    Not a complete failure of the gearbox, but those gears! For not having a fuse in the circuit, the contacts on the trigger assembly cleaned up well with piece of leather. The cutoff looks new and the semi-bump on the trolly does not look worn. None of the OE wire had noticeable degradation and the OE motor is still strong. Those are pieces of the gears laying on the wire behind the trigger.

    Some time before the gears failed my friend complained that semi-would-fully; I think it was the lobe on the sector gear? I could rest the cutoff in position and trip the cutoff release using my fingers, but the sector gear pictured was not fully engaging the cuttoff lever.

    IMG_20180425_220348089_edit.jpg

    Seems the only thing keeping the M15 from spinning and using the semi feature is the gears. I live close to Thunder Kiss NW, so I went there for some gears. Picked up steel, house brand gears(TKNW) with the OE 16:1 ratio. Shimmed, timed, assembled, connected to a 7.4v 1600mAh; it lives!

    It cycles semi and fully like garbage on both a 7.4v and 9.4v. For $48 and my own work, it's a cheap, properly used rifle. My first mid-range scenario AEG. Now backup for my TM Desert Warrior 4.3

    This AEG was given to me. The initial cost of this AEG at release was $249usd. So I figure, WTH, lets give it an upgrade without going over the cost of the current MSRP of the equivalent CA sportline model, until I break the body...
     
    Last edited: May 11, 2018
  2. Rainmaker

    Rainmaker New Member

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    I picked up the A&K floating hand guard and CTS stock for less then $50 off Evike. I took the grip to the belt sander and removed plastic til the gearbox mated with the grip where it screws together.

    IMG_20180510_121918982_edit.jpg

    I went back to TKNW and picked up a piston, piston head sealed nozzle and a few o-rings; checked the shims, added Buzzy's Slick Honey to the gears and DOW33 to the piston/cylinder. Reassembled and tested with one high-cap mag stuffed full, using a 2 year old Nimh 7.4, 1600. It's working, it fires both semi and fully consistently, but it acts like it's going to jam up under heavy use.

    The AEG on an old paintball chrono is getting 330fps(+/- 4fps) with .25g bb's in semi-auto; in what measures at an inside diameter of 6mm at the exit of the CA OE barrel. The chrono was horrible at registering full-auto, but did give readings around 330fps when it did read. Decent with the OE spring, but it's bothering me that I can't find specs on what OE spring was installed by Classic Army?

    I did fire the gun when it was new, so I know how it felt then. I'd say that the compression is far better than OE compression, the ROF has slightly increased from OE ROF; but, the trigger response at this point is still garbage. From compared to when I played speedbal-paintball with micro-switches anyways.

    So I do a little more reading, and make another visit to my local airsoft parts supplier for a new battery, PicoAAB and some wire. However, they didn't have the low resistance wire so I had to order that and wait a week... [Waits a week]... Reassemble with wiring to the rear, good shim job, new gears, new piston/head, new wire(my fourth soldering job), mosfet and new 9.4v, 1600mAh. I'm now $109 into this AEG.

    IMG_20180510_123805070.jpg

    IMG_20180510_123330770_edit.jpg

    Shot through three high-cap mags, switching back and forth from semi to fully with no jams. CA OE motor got warm, but not hot.

    Another stress test aside, lets look inside...

    IMG_20180510_125146782_edit.jpg

    IMG_20180510_125421178_edit.jpg
    Got a thing to do, be back to update...


    ... Update...

    Spring: CA OE?
    Piston/head: SHS 14 tooth steal High Speed piston - Matrix Mushroom piston head
    Cylinder/Cylinder Head: CA OE
    Tappet plate: CA OE
    Nozzle: TKNW dual oring
    Gears: TKNW 16:1 steal gears with internal bearings. Shimmed
    Bushings/Anti-Reversal: CA OE
    Trigger Switch/Trigger: CA OE
    Motor: CA OE
    Wires/Mosfet: Gate Silver low resistance / Gate PicoAAB
    Hop-up: CA OE two point bucking
    Inner Barrel: CA OE 6.05mm(garbage)
    Battery: Various
     
    Last edited: May 15, 2018 at 5:56 PM
    ma_airsoft likes this.

  3. Honeybadgerz17

    Honeybadgerz17 Active Member

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    Bellevue
    Sounds like a fun project gun. I mean who doesn't want a free rifle to turn into a beast!
     
  4. Rainmaker

    Rainmaker New Member

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    I've tuned five aeg's from two friends into durable aeg's. Minus buying metal receivers for three that are nylon composite. So at least I was able to get familiar with the tech before haphazardly spending money on components that have bad compatibility issues.

    I never expected a free rifle, and this will do just fine.

    Edit: I do have a question. Does anyone know of the OE spring rate equipped in the CA M15a4 Sportline?
     
    Last edited: May 15, 2018 at 4:54 PM
  5. Rainmaker

    Rainmaker New Member

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    I've looked around at specifications for this CA series of rifles and those like the CA M4A1 RIS built within the last few years by CA, and they are spec'ed at 330 to 350 fps, but with no indication of what spring is used.

    As stated before, I'm getting a consistent 330fps(+/-4) with great compression off the OE cylinder and cylinder-head(w/ padding). No idea of what it chronoed before its gears pooed the box? I'd imagine that when I get a 'spring-guide with bearing' the extra preload on the spring from the thickness of the bearing will increase the fps some. And supposedly increase the ROF 1 to 3.

    I flipped the aeg and did a paper-towel-ball test on the hop-up to see if it was pushing or sucking air through the feed port. It sucked the paper-towel-ball in a little with each shot; 3 shots total. The King Arms mags connect with the hop-up very well and have shown no signs of improper feeding. Even now with the increase in ROF due to the upgrades, everything seems to fire and recycle without issue, until the mag spring loses tension... Back to that sucking nozzle!

    I was reading around places and found this... My cylinder has no holes. I was thinking that with the 3/4 hole cylinder that more air would be able to get behind my piston head faster to refill the cylinder as it recycles, so that the piston was not sucking from the nozzle as it recycles. Will this work?
     
    Last edited: May 15, 2018 at 5:38 PM
  6. link0

    link0 Active Member

    254
    169
    San Jose
    Looks like your build is coming together nicely. I'd add a neo magnet 16tpa balanced motor and call it a day. I love a snappy trigger response.
     
    -Spitfire- and BOA_SP3CT3R like this.
  7. Rainmaker

    Rainmaker New Member

    15
    3
    PDX
    Got to do the barrel. And even though I don't have sights, I think the barrel should be next. The CA OE barrel looks like a kaleidoscope, though it has a mirror finish. Needs a straight bore, not a ripple bore.

    What I want from this aeg is internal durability, accuracy and realism. Not so much concerned with ROF; which goes hand-in-hand with "snappy trigger"; though with my upgrades the ROF will have increased from OE. However, as I'm looking for realism in this, 30/60round mags will be the norm as I'll be counting my shots most the time.

    Though, once I have a new SS barrel, hopefully in 6.03mm R-hop, motor or possibly a metal receiver would be my next want.

    Come on King Arms, email me back!
     
    Last edited: May 15, 2018 at 5:47 PM
  8. BOA_SP3CT3R

    BOA_SP3CT3R Well-Known Member

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    Bull Shoals
  9. link0

    link0 Active Member

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    San Jose
    You can improve trigger response without increasing the ROF too much. High torque motors have much faster acceleration from stop, but not much top speed.

    I am mostly a semi-auto player, so I also don't care about ROF at all. If anything I prefer really slow ROF, as it wastes less ammo. A fast trigger response can make the difference in CQB.
     
    Last edited: May 15, 2018 at 8:56 PM
  10. Rainmaker

    Rainmaker New Member

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    PDX
    That's pretty much how I feel. Though, I'm going after the realism aspect. AR15/M16/M4 all spec out to 700 to 850 rpm. With averages that works out to 13.8 rps/bps, or 14bps. Going to use my friends laptop, my mic and the software I got off this forum to find my rps. If it's too high, maybe, possibly, after getting a SS barrel, HT motor and metal receiver, I'll spring for a ROF controllable Mosfet instead of using a lower battery voltage to decrease rps/ROF.

    I wish there were some type of markings on my CA OE motor so I could know what its spec is?
     
  11. Rainmaker

    Rainmaker New Member

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    3
    PDX
    With "Broken Free" I was given three bags of .25...

    I've been testing with .25 in a 6.05mm x 363mm for a consistent 330fps. So I'll probably use .23 and .25 in this. I'm thinking that .28 will probably increase the fps to around 340-365... With this barrel and cylinder configuration.

    If I move to a SS 6.03mm barrel, I'll probably get an fps gain with .25 that will make me change to a softer spring to get back down to the 330's, 340's.

    Still looking around the nets for an answer to my previous question...

     
    Last edited: May 17, 2018 at 4:30 PM
  12. cetane

    cetane Active Member

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    91
    Markham & Stouffville, Ontario, Canada
    Curious why a CA has/had king arms gears in it...? Previously changed out?
     
  13. Rainmaker

    Rainmaker New Member

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    PDX
    I am curious about that as well.

    The gearbox and broken gears are all OE, but are the cheaper King Arms components. I've looked around the nets and came up empty trying to find if CA and KA have done work together. A few YT break-downs of the CA Sportline M4a1/M15a4/M16 all have KA gearboxes and gears. So either CA owns KA, or they have worked in collaboration.

    If I could get Hop-up cases from both companies and take measurements; I'd bet they are using the same schematics across multiple parts. That's why I'm considering getting a KA receiver as the description states that KA receivers fit CA gearboxes and hop-ups without modifications.

    Well, I did find this... https://store.classicarmyusa.com/products/king-arms-ultra-grade-type-3-aeg?variant=5273848250402... It's interesting to me as KA has Eagle Force under it.

    Seems I can not contact CA to ask as their required field for phone# does not accept 10 digits.
     
    Last edited: May 16, 2018 at 5:39 PM
  14. Rainmaker

    Rainmaker New Member

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    PDX
    Matrix Godzilla or ZCI Balanced?
     
  15. link0

    link0 Active Member

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    169
    San Jose
    I have no experience with Evike's house brand, Matrix. I like ZCI motors though.
     
  16. -Spitfire-

    -Spitfire- Well-Known Member Supporting Member

    2,097
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    Martinsburg
    It's worth pointing out that 7.4 and 9.4 Nimh batteries don't exist. What you likely had was a 7.2(basically the weakest battery you could get lol) and your current battery is a Valken 9.6 1600mah. Do yourself a huge favor next time, and pick up a 7.4 lipo. The performance will be similar to a fully charged 9.6 Nimh, but way more consistent.

    And the Matrix Godzilla is 24tpa iirc... Way to high for your current ratio/spring. Unless you intend to install some low ratio gears, or a crazy strong spring, I'd go with an SHS high torque instead (ZCI balanced is almost as good as the SHS high torque).