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-   -   Tanio Koba / KJW M4 GBBR Basic Information and FAQ (

Wilson March 9th, 2010 04:45

"Metal" is too vague. What material is it made out of? There are MANY plastics that are stronger than the pot metals frequently seen in airsoft toys.

andrew321 March 9th, 2010 18:10

Man, no kidding. Anyone that has a lifted truck has seen the "plastic" lift blocks that can hold a 1,500lb truck body on while its being thrashed around...and not wear down. But for some reason my gear box couldnt stay together for more then 5,000 shots:cool:

I am also really interested in what the options for mod-less inner barrels are... Anyone??

azulikit March 14th, 2010 13:43

Mod-less TBB are available for this gun. They have standard and custom lengths available.

You can contact Travis Humble at Here is a note from him, Barrels are still available and can be custom made to any length you specify. Cost is $45 + shipping. US Domestic is $5.75 and International is $14.00.

You can also contact AKA on ASC KGBB he has mod-less EdGI TBB available. PM him, he seems pretty knowledgeable on it.

dotty3107 March 14th, 2010 14:36

Thank you azulikit for the info. This is very helpful :)

kylem_8 March 14th, 2010 18:40

Information on replacing a clear receiver for a metal one

I am going to assist anyone that is considering replacing the Clear Plastic Lower Receiver with a Metal Lower Receiver. The following is information on the problems that I experienced when converting the KJW M4 to a full metal gun.

Firstly, if you don’t know anything about GBBR or their real steel counterparts when it comes to the trigger mechanism, DON'T ATTEMPT TO DO IT YOURSELF. There are many small pieces and springs in the trigger mechanism that if you disassemble (which is very easy to do), you may either loose the piece, or forget how it goes together.

If you do know how to work with the trigger mechanism, then you'll do just fine transferring it over to the new metal receiver.

The issue came about when trying to remove the buffer tube from the clear receiver. There is a steel ring that holds the buffer tube securely into the lower receiver. This piece could not be removed without damaging the plastic receiver. It is made by the forces of God himself to make sure that your buffer tube never leaves the Clear Lower Receiver. Absolutely every attempt was made to try to simply unscrew the brass buffer tube from this steel ring with it turning 1/4 of a turn. All sorts of tools were used with no success. Even using chemistry (heating and cooling the parts for expansion and reduction of their overall size) did not work. The chemistry method was used because of the suspected use of Red Locktight (which was confirmed later on). I was hoping to crack the glue. That didn't happen.

So, with me frustrated out of my mind I was left with only 1 option. To cut it out of the receiver. THIS WILL RUIN YOUR PLASTIC RECEIVER. But, who cares. You now have a metal one. Why do you need the clear plastic receiver?

Once you have the steel ring removed from your Clear Lower Receiver (the brass buffer tube is still attached), the issue remains of unscrewing this steel ring. There is only 1 option (Which is very easy to do). You must use a Dremmel with a cutting tool to CAREFULLY grind down 1 of the notches. You will know that you've gone far enough because the steel ring actually snaps open. That’s right, the reason you have such a difficult time unscrewing the brass buffer tube is because the steel ring is pressed onto the buffer tube.

Now that you finally have just the brass buffer tube in your hands its time to screw it in to the Metal Lower Receiver.YAY. But, this will most definitely take some muscle to do. KJW has painted over the threading so you need to just keep working the buffer tube in to the receiver so the paint comes loose and gives way.

At this point I must let you know that you must screw it in all the way until the greyish silvery piece that actually holds the buffer piston (I think that’s what its called), inside the buffer tube. If you do not screw it to that part, when you cock your weapon, it will only come back half way. The issue was that the Bolt Carrier got stuck on this piece. Which meant that I had to unscrew the brass buffer tube and push down on that greyish silvery piece so the bolt could move fully forward.

So, now you should have a full metal KJW M4 in your arsenal.

Hope this helps when you get your metal receiver.



jareyes March 14th, 2010 19:56

I would just like to add that short of dremeling your way through that steel nut, there are other methods if, for some odd reason, you DO want to keep your plastic lower receiver or just want to know how to take it off without destroying the gun in the process.

I followed a few of the steps outlined above, namely the manual torquing, and heating up methods. Neither worked so I figured it might be loctite too, let it soak in solvents for a bit but that didn't work. As a last resort, I used some liquid wrench and put some on the edge of the threads; let it work its magic. After about 20 minutes, my brother and I took one wrench each, put one wrench on the steel nut and another wrench around the bronze buffer tube inner part, with a rag wrapped around it to protect from scratching it (I still managed to scratch mine a bit though, be warned). We torqued in opposite directions and the nut came off after a lot of elbow grease.

What probably happened is that the cheaper metal of the buffer tube and metal of the steel nut galvanized after they assembled the gun, liquid wrench is a good bet for anyone that wants to do this, plus you can just wipe it up if it hasn't worked; no damage or anything.

Hope that helps.

prepaidpwnage March 14th, 2010 20:26

Great running thread over at Arnie's on this. I love my KJW m4.

A member over there (and here too I think) runs a nice online shop with some products that he made for the KJW m4, have a look. He is working on PMags for it.

Sorry if this is a repost, been a while since i visited here as I have not played too much airsoft, and I've been busy with real steel stuff.

Rookie Ab March 14th, 2010 21:06

Just wondering if this is the lock ring you are talking about?I have not had the pleasure of a clear lower yet, but I'll assume it's the same as this one.[/IMG]

The lock ring on the outer buffer tube, if this is the ring your referring to,it is part of the KJ outer buffer tube. It has no use but to make it look like the RS counter part.The outer buffer slides over the inner brass tube and is held together with the receiver extension cap(part #52).And there is a set screw About 1 inch from the back as you can see in the photo.It keeps the outer from turning on the inner.

If you unscrew the extension cap (#52) and remove the set screw the outer slides off easily .

jareyes March 14th, 2010 22:14

No no, the parts described are for the inner brass tube and the nut embedded in the receiver that the brass tube threads onto. That one is a monster.

Rookie Ab March 14th, 2010 22:56

:oops: I knew there must have been something different about the two receivers. But even on the metal lower they used a glue,loctite,something that didn't want to let go either.

andrew321 March 15th, 2010 23:44

I'm checking in to see if "cansoft" or cradle knows about the stock and front set compatability... but does anyone know if i should order an AEG stock, or the WA GBBR stock... It doesnt seem as if a AEG will work, because they use a straight through screw to attach..

Kody, how'd you do yours?

Rookie Ab March 16th, 2010 20:15

Well the first thing ,is that no other buffer tubes will fit the KJ, They use a two part buffer tube. That is their own design (a little weird I think).

If you really want to put that stock on,then you will have to make and mod something so you can do it,until more accessories start to hit the market.

I wanted a Magpul UBR on mine, everybody said it couldn't be done :rolleyes: so that was my incentive to find a way.I had to drill and tap one hole to hold the UBR on ,using the screw that came with the UBR.And I found a way to leave the inner brass buffer tube intact.

The full stock you are interested in could be done but would need a little more head It's about 3 inchs longer that the KJ inner buffer tube.Would need to fab a piece to extend the inner buffer tube in length and girth. Then the stock could be held on with the proper screw.The other problem is how the front of the stock would mate up with the receiver end plate,(part # 51) :banghead:

Do you know anyone that could make new buffer tubes? I would order a couple ;).

baker_Jeff March 16th, 2010 20:19

I'm using a real steel Magpul MOE stock on mine, mil-spec.


andrew321 March 16th, 2010 22:24

Goddamn, This is going to be frustrating to get this done. but a GBB SR-25 will be worth it when its together.

Out of the ASC combined knowledge, can we find what one would need to more or less make a kjw m4 into an SR-25?

Edit: By the way, I could fab a couple trial buffer tubes up...How would we want them to be different?

FridayNightGamer March 17th, 2010 20:38

The SR-25 is in a different calibre, how are you planning to make it?

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