KJW M4

[wotty33]

Theyre done, and have been tested as well. Full length TB barrels are being made now.

i'm guessing full length TB barrels couldn't be brought down to 350 fps with the new regulators?

[t_hum]

Of course velocity is very temperature dependent, but I would say yes, the new valve should be able to drop fps to sub 350 at reasonable temperatures with the TB. Its hard to say just how much harder the gun is going to shoot at this point, however.

[sacairsoftsn00py]

So long as it shoots under 400 FPS with .20g BBs.

 

For those with a 1 joule limit, you could always cut down the inner barrel down to "pistol length" and use propane/green gas.

 

The reason I use propane is that duster gas cools down much quicker. The higher pressure allows for much better/ snappier shooting. Propane cycles the bolt carrier group better. Specially during cold weather. Summer time, its back to duster gas.

[danielsilva]

kjw has a 14.5" outer barrel...it will stick out 1.85 inches from the ris

 

That's roughly 40mm ( don't use imperial ), i can live with that.

 

Anyway i've seen some threads back someone that said that they installed a Marui P226 inner barrel and it worked. Is it confirmed ? Cause if its true i hv a nice PSS10 inner barrel for the VSR that would be a great addition to my KJW once it arrives!

[sacairsoftsn00py]

A few pages back, someone posted a photo of the KJW M4 inner barrel alongside a TM GBB pistol barrel and a VSR barrel. They are all different in spec.

 

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Just got my replacement bands and hop buckings. They stuck in more than what I originally inquired about. LoL!

Edited November 18, 2009 by sacairsoftsn00py

[t_hum]

Just posted a video showing how the parts get installed.

 

 

Site will be up in a few days.

[MrTreble]

Nice video. Is that your KJ m4?

[t_hum]

Thanks. Yes it is.

[sacairsoftsn00py]

Good deal dude

 

I've been waiting some time for this. I keep refreshing the tab opened up for the site.

[SwatMP5man]

Nice video t_hum, parts look great and that's really going to help with installation.

[Donut]

Awesome t_hum.

 

[sacairsoftsn00py]

Raven1...and now me.

 

 

Fail?

 

I would say not completely.

 

My piston cup is in fairly decent shape. On one full charge of propane, I was able to empty 120 rounds on semi auto.

 

I am running the gun without the detent pin for the recoil buffer and the gun performs as it should.

 

Roughly5000 rounds have been put through the gun with temperatures varying from 50-70 degrees almost exclusively using propane.

 

-------------------------------------------

 

EDIT:

 

Just went through a few more magazines on semi auto. The gun shoots flawlessly.

 

BUT....

 

a reliable full auto is dead. It shoots full auto though there are some light strikes. Also, when doing bursts the gun sometimes half cycles...lets out a puff and would require manual cocking of the charging handle.

 

Personally, this doesn't bother me as the gun shoots a whole lot better on semi auto. Onn full auto, you end up with a cloud of gas venting from the ejection port. If your propellant has silicone on it....it will get into the hop bucking and affect accuracy.

 

I might leave it at this for a little bit.

 

I am however contemplating on making a Rubber buffer for the end of the buffer tube. I am thinking about putting in a buffer so the metal recoil buffer doesnt hit the metal end cap on the buffer tube.

 

I'll have to swing by Lowe's tomorrow and see if they have any material that would work well as a buffer.

Edited November 19, 2009 by sacairsoftsn00py

[MrTreble]

That's a shame... maybe if that part was designed like the RS, it wouldn't have this problem. Then again, this was designed to use 134a gas. 5k-10k rounds is still far better than any WE or WA platform I've read about.

[Me4noreason]

That's a shame... maybe if that part was designed like the RS, it wouldn't have this problem. Then again, this was designed to use 134a gas. 5k-10k rounds is still far better than any WE or WA platform I've read about.

 

I've read about a WE getting 10k. However it wasn't a test but rather a guestimate.

[sacairsoftsn00py]

That's a shame... maybe if that part was designed like the RS, it wouldn't have this problem. Then again, this was designed to use 134a gas. 5k-10k rounds is still far better than any WE or WA platform I've read about.

 

Well, KJW could have decided to put more material in there. They could have made the part that gets broken twice...or maybe even 2.5x of what it is. There is room to do that.

 

Its a design flaw that could be easily corrected.

 

By doing it that way, the back tab of the upper receiver also ends up supporting the stress of the buffer hitting the detent pin (that I suspect ends up cracking the part of the lower receiver).

 

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The incident doesn't bother me one bit. If I wanted full auto....I'll just bust out my other KJ Or maybe bust the other one too...

 

 

What my M4 currently looks like right now.

 

Magazine is not dirty. Its condensation from emptying 6 (32rd) magazines on semi auto at~50 deg. Fahrenheit in consecutive shots pausing less than 1 second in between shots.

 

 

Full Auto bursts w/ propane at ~60 degrees

-notice the cloud of gas...can't be too good for accuracy with the silicone going everywhere

 

Semi Auto.

-No cloud of gas. Much better

 

 

Edited November 19, 2009 by sacairsoftsn00py

[Donut]

Mine's still holding up just fine

[t_hum]

Any guesses as to why the broken detent leads to the cloud of gas? Raven had the same report when I last spoke to him.

[MrTreble]

Mine's still holding up just fine

 

 

You probably don't shoot it as much.. what's your round count?

[stickyittoyou]

Any guesses as to why the broken detent leads to the cloud of gas? Raven had the same report when I last spoke to him.

 

T_hum is there any way of producing a piece that can support it and be connected to the body by the back receiver pin? or does the hammer and the rest of the trigger assembly get in the way? I'm just trying to see if there could be a small block of metal cut in areas so that it does not get in the way of the mechanisms and yet supports the back of the receiver. Do you get what I am trying to get at? I really can't describe it... and I'm not good at drawing something out on the computer. lol

In this picture I see PLENTY of space that can allow for a block to be placed in there to make it more durable. T_hum I know you can do that... that would be an easy fix. The only down fall would be that the pin would be MUCH harder to pull out. On the bright side there would be less play for the upper receiver.

 

My guess would be due to the buffer springs being relaxed more into the upper receiver causing a longer delay from being away from the nozzle on the magazine causing gas to spew out, say if the gun was in it's prime... the nozzle would be connected to the nozzle on the cup. Due to there being a longer cycle from the spring being relaxed it takes longer for the small gas release button on the magazine to be released. Thus requiring more gas to be pushed from the magazine, but by the time there is more gas from the magazine being pushed out the nozzle is already in it's cycle. Sorry if this made no sense...

 

 

 

P.S. Can someone get a good picture of the upper receiver from underneath it Rail and front sight aimed down. keep the bolt carrier assembly in it as well. I want to see what it looks like... gosh I really need one of these....

Edited November 20, 2009 by stickyittoyou

[Kai_Wolf]

Awsome vid T hum, very impressive and quite fast!

[sacairsoftsn00py]

I will post my thoughts on things when i get on a computer. Out right now with my girlfriend and friends at the theater. Midnight showing of the twilight saga...new moon!

[AirSoftNJ]

I Have Seen Great Things and Ok Things from the KJW and Its Time I pick One Up and Trade in my WE SCAR. Just One Question did KJ Stop Making Them? They Are OUT OF STOCK. EVERYWHERE!

[Speed=]

As far as I can tell airsplat has them in stock. They don't have anymore mags for sale though and I believe they only have the serialized version.

[t_hum]

I think what we are experiencing is a shortage due to one of two things (or both): 1. gun is increasing in popularity and demand has exceeded supply for the time being. or 2. KJW is perhaps fixing a few body issues which has put production behind.

 

For KJW's sake, I hope they fix the body issues at the factory. This is pretty much the one flaw of the entire system.

 

 

As far as reinforcement parts go: yes, I could make up some kind of tab. I would make opening the receivers tough. Teesting of the product would be difficult as failures haven't occurred systematically. Ill see if I can rig something up today while Im at the shop.

 

My other thought was perhaps redesigning the detent so it allows the buffer to sit slightly further forward thereby spreading its load out over the detent, carrier, and guide rod end. Right now there is an ever so slightly gap between buffer and carrier, allowing the detent to be hammered on.

[wotty33]

I think what we are experiencing is a shortage due to one of two things (or both): 1. gun is increasing in popularity and demand has exceeded supply for the time being. or 2. KJW is perhaps fixing a few body issues which has put production behind.

 

For KJW's sake, I hope they fix the body issues at the factory. This is pretty much the one flaw of the entire system.

 

 

As far as reinforcement parts go: yes, I could make up some kind of tab. I would make opening the receivers tough. Teesting of the product would be difficult as failures haven't occurred systematically. Ill see if I can rig something up today while Im at the shop.

 

My other thought was perhaps redesigning the detent so it allows the buffer to sit slightly further forward thereby spreading its load out over the detent, carrier, and guide rod end. Right now there is an ever so slightly gap between buffer and carrier, allowing the detent to be hammered on.

Do you think the "one flaw" is basically the fact they've used pot metal on the receiver to make it affordable?

 

I guess a good aluminium or steel receiver is the answer. Presumably whatever they reinforce, the stress will just go somewhere else if the materials too weak.

Edited November 20, 2009 by wotty33