• Baby's first M4. (or, FloaterTWO builds a gun)
    41 replies, posted
So for ages i've been thinking of buying a cheap, shitty second hand-M4 to work on as a project gun to learn how to fix and build gearboxes and whatnot, and also so i can have an M4 to play around with. My brother was very supportive of this, and basically gave me/loaned me a huge heap of M4 bits, to start me off on building a gun. [IMG]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3181.JPG[/IMG] So i decided to make this thread to show the progress since i thought it might be interesting as I've never even opened a gearbox myself before and have no idea how to do anything. This is the contents of the box my brother gave me: [IMG]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3182.JPG[/IMG] In here are: King Arms H&K marked M4 body Front wiring Rear wiring Gearbox case (cracked at the front, so i may need to replace eventually but it's good for now.) Motor (no idea what kind but it'll work aparrently) Barrel (thread on the end is stripped as it broke when he was tightening a RIS rail onto it or something, more on this later though). Front sight + faux gas tube Carry handle Pistol grip Piston Piston head Spring guide ...and a whole other bunch of bits i don't know what to call. I have no hop unit or inner barrel, no handguard, and no flash hider. I'm planning to try and locate a second hand M16 front end and inner barrel and whatnot, but i can't do anything about that just yet, as the forums i would usually look on for parts are currently down. I may be missing a few gearbox parts too but my brother definitely has them somewhere. First step is to put together the gearbox to try and get it running, so let's get started. Immediately i've run into two problems. Firstly, I have no idea which side of the gearbox to start putting things in. [IMG]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3183.JPG[/IMG] Secondly, I always thought the piston head was attached to the piston somehow, and i don't see any way of attaching the two. [IMG]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3184.JPG[/IMG] Not a really good start.
Put the bits into the left side of the gearbox. (the one on the right in the second to last picture) And the piston head is already on the piston. That other piece is the cylinder head
Piston and cylinder head fit inside the cylinder, but its a loose fit, another piece holds the head in and the spring guide holds the other end.
Holy shit is that a Warhammer 40k Rhino Toy?
I figured out how things go together and now i have to put the shims on the gears. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3185.JPG[/img] Did two of them, but they still grind a bit so i'm trying some other gears to see if it fixes them. And now i know how the piston goes together thanks to notrabies [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3186.JPG[/img]
You should probably buy new shims before you move on here, a good shimming is probably one of the most important part of a good gearbox. Oh and the long, thin, and oddly shaped piece in between the pistol grip and stock holds the cylinder head on when everything is in the shell.
if it grinds, you need new shims
I managed to get it pretty good, but the gears were grinding against eachother. I can't quite get them to work again properly though. Might do it when it isn't late and when my brother isn't asleep so i can get it to work all nicely. In my current state of tiredness i managed to get a bushing jammed on the end of this gear. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3187.JPG[/img] My brother found me a pack of bushings that match so i'll have one last attempt at shimming it tonight before saying 'fuck it' and tossing it all into a box to work on tomorrow and over the weekend. To take a break from the gearbox i put the handguard he found out for me together and assembled everything else roughly. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3188.JPG[/img] I quite like how it looks. Simple and generic, but it's still nice. The MOE pistol grip he found out for me that aparrently fits the wires better looks like ass though. Update: [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3189.JPG[/img] New bushings and gears worked. Now it seems alright. Going to pack shit up for the night and see what my brother thinks of it tomorrow. Hopefully i won't have to re-shim it again.
So after much swearing and annoyance and learning how to use a multimeter to find out why the trigger block wasn't working properly, i got the gearbox together: [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3192.JPG[/img] It grinds really loudly and is probably really badly shimmed, semi-auto is just a slower full-auto, safety doesn't work, but it lives. I put it together in the rest of the gun just to see how it looked overall. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3198.JPG[/img] Next step is buying a proper gear set so they'll work together properly, finding out what I'm missing to make the semi-auto and safety work, and finding a hop-up unit and inner barrel. I'm just pleased i put it together and it worked, albeit badly.
Seeing you go through all of this reminds me why I love gas guns and how much it's easier to take apart. Great work so far buddy.
Looks great
Thats pretty smexy
The camera i was using ran out of batteries whilst i was looking to see if it had a video recording function so i had to make do with my phone [media]http://www.youtube.com/watch?v=zVKegcGVvrs[/media] Excuse the super shaky gun and my terrible voice. I can't really do a lot to it right now since I'm waiting for gears and stuff in the post, i might look into what's making the trigger stick back though.
aye yer a wee southern wanker prick AYE fuck
Most of the internals are TM, correct? You might end up needing to just replace the trigger mech
I doubt any of the internals are TM, the piston and spring are most likely ICS, no idea what anything else is. I've got to take it apart to get the wiring out so i can fix it up a bit so i'll take a look.
So the gearbox case i was given by my brother is on the verge of exploding, the small crack that was in the front is now all the way through on the bottom side of the casing and starting to show on the top part, it won't last a lot longer. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3201.JPG[/img] So now on my 'to buy' list are: Motor (Current one is old and probably the cause of the horrible noises) Pistol grip (The one i've got is kind of shit and the motor doesn't fit too well in it) Gearbox Casing (Mine's about to explode as mentioned above) And some other stuff too. New case is the most important part i need, but i'm going to try to have to see if i can find a second-hand one for sale anywhere since the new ones start at around £35 which to me seems a lot for just a chunk of metal
[QUOTE=Inafinus :3;32442266]aye yer a wee southern wanker prick AYE fuck[/QUOTE] blud don't test us Southerners, ya get me?
Also, i discovered what was causing the trigger to stick When i was looking for springs to put on when i was putting together the safety lever, i picked one up and asked my brother if it was the right one "no, that's the trigger spring" I thought the trigger was just pushed back by the spring on the contact block it pushes, it must've been slipping off the contact block when it went forward. Going to try putting it together to test it out again tomorrow, would do it tonight but it's 2am and everyone's in bed.
have fun putting that trigger spring in, that thing makes me want to kill myself
putting gearbox's back together in general makes me want to kill myself.
i agree with both of you now I got the new gearbox case, barrel and hop unit. I tried out the trigger spring in my old gearbox case, piece of piss, no difficulty there. Now i try to put it together in my new case with my ~nicely shimmed gears~, the fucking anti reversal latch keeps jamming itself into the bottom gear and getting stuck and off-centre, the trigger and spring keep exploding out, and the cylinder was too big before i changed it, which was fucking annoying because i got EVERYTHING to line up perfectly in the back half of the gearbox, but the cylinder was slightly too long and wouldn't close at the front, so i had to take it out and now it's being shit and nothing fits. Here's the gearbox in its current state, going to try putting everything in again in a minute. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3204.JPG[/img] And i lost the big table since it's a pain in the ass to haul up from the garage so i have to work on the edge of my desk. [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3203.JPG[/img]
Lookin' good, mate.
[media]http://www.youtube.com/watch?v=ZDT-FEKOoy8[/media] After much Dr. Pepper, swearing, sweat and frustration, i got it all together and sounding nice. Then my brother gave me the[B] ULTIMATE GIFT.[/B] [img]http://dl.dropbox.com/u/9988278/airsoftARproj/DSCN3206.JPG[/img] Pretty much done apart from a few minor external tweaks. I need to find the bolt catch pin since it fell out, and i need a LiPo battery to fit in the foregrip. Going to chrono it soon and then field it at the next game i go to. I'm surprised at how quick it's come together.
[QUOTE=tommyc225;32448309]blud don't test us Southerners, ya get me?[/QUOTE] AYE'LL FUKIN CHIB YE WIE ME BOTTLE AY IRN BRU YA FUCKIN WE BAWBAG
[QUOTE=FloaterTWO;32461992] Pretty much done apart from a few minor external tweaks. I need to find the bolt catch pin since it fell out, and i need a LiPo battery to fit in the foregrip. Going to chrono it soon and then field it at the next game i go to. I'm surprised at how quick it's come together.[/QUOTE] Good work! It certainly needs a lipo, which you should really save up for and buy new, but its sounding pretty decent. So yeah, new motor+new pistol grip+flashhider=good-to-go?
The end of the barrel has a mostly stripped thread on it, which is why my brother gave me it. I don't really mind the lack of flash hider, only way of fixing it would be to machine it smooth then wedge one onto the front. Pistol grip i initially hated, but i've grown to like it. Might respray black, though. Motor is pretty nessecary since i think my current one is rather terrible and squealy. There's an airsoft arms fair the day before the next game i'm going to, so i'm going to try picking up a grenade launcher sight and see if i can find any magpul pistol grips, hopefully i'll find a motor before then since a motor change is something i don't particuarily want to do the night before a game if it ends up not owrking.
God the M203 plus MOE handguards looks so sick.
it looks a little bit like the m203 heatshield. probably just the angle and the lighting
That's a sweet lookin' gun. In the name of all of us, the "guns can be opened? What does this piece do? Oh God what the fuck what the FUCK" players, I salute you.
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