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The Ultimate KJW M700 Upgrade Guide

193307 Views 326 Replies 68 Participants Last post by  Baumi
Hey guys!
So I got a request for a build thread on my KJW M700. I know a pretty good amount on this gun, so I thought, why not help others in the process? I also noticed that there isn't really a guide for those with KJW M700s, like 1Tonne's VSR guide, or the Holy Grail to your DMR. Here we go!

First off, there are different routes for upgrading your M700, and this guide shows the many different ways. This means that you need to look and make sure that you are going to route you want, not just linearly going through the guide. Please read the entire guide before attempting upgrading.

The second thing you will need to know is this- If you ever get stuck, EVER, the best thing to do is to put everything down and take a break and think about it. If you still cannot come up with a solution, contact someone. This way there is a much better chance that unnecessary money will not be put into the rifle due to ignorant mistakes.

Lets begin with where I purchased most of everything.! The transactions were smooth and coast to coast shipping went well. Most of the links I provide are from Evike when possible. Just remember that sometimes you will have to venture out to other companies to find you need.
General rule of thumb- if you're not buying what you really need/want, you are wasting your money. Put the extra money into what you really need, not whats cheaper or more convenient.

This guide will take you from this:

To this!

So here we have the gun: Airsoft Guns - Airsoft Guns | Airsoft Guns - Sniper Rifles |
If you plan on buying a KJW M700, do yourself a favor, and buy the standard version! The take-down version will be nothing but a pain! (Don't worry, that ugly front sight comes off!)
Being a green gas/propane powered sniper rifle, the M700 does not perform well out of the box. The PSI of the gas with vary, considering as gas expands it cools, and the colder the gas becomes, the less pressure is inside the magazine. Green gas is very effected by the cold. With this type of power source, expect to see shots that are inconsistent in range and accuracy, in other words, not good for a sniper rifle!

HPA and CO2
This was the first thing I changed (and you should too). I purchased parts from to build an HPA rig. An HPA rig (If done correctly) will keep the PSI of your rifle at a constant value. You should be seeing no more than a 5 PSI difference between shots. This is probably the trickiest part in upgrading you M700, but the best thing you can do. You will first need to drill and tap a 1/8th NPT hole into your magazine. If you do not have the tools, or do not feel comfortable doing this yourself, you can have Palmer's Pursuit Shop do it for you. But if you want to do it yourself, look here: (Thanks to dobey for that!)

First and foremost, I purchased a Tanaka Long Magazine (Tanaka 29rd Hi-Cap Gas Magazine for Tanaka M700 Series Sniper Rifle, Accessories & Parts, Airsoft Gun Magazines, Gas Gun Magazine, Tanaka GGM - Airsoft Superstore). The setup below is based off of this.
There is an alternative to the Tanaka magazine if you'd like the extra rounds without the cost. This magazine is made by Action Army and is nearly identical to the Tanaka, from what I've read. The only downside is that the shell is actually plastic. Here's the link:
AAC-21 28rds Gas Magazine ( Also Work with KJW / Tanaka M700 ) by:

The standard 10-round magazine can still be tapped, nearly all gas magazine can be, but having to reload every ten shots makes it nearly worthless.

Using CO2 in the Stock

These links should be just about everything for having your setup housed in the stock.
(Ok wow… Everybody please thank for recognizing the KJW users, they simplified everything since I first posted :D)

So now everything is consolidated into this:
KJW M700 Macro Line Hose Kit - Airsoft Regulators - Airsoft

This comes with your regulator, fittings, long magazine parts, QD fittings, etc.

Now you just need a smaller gauge like this:
Freeflow 300 PSI Mini Gauge [PNEU029] - $12.00 : Palmers Pursuit Shop, Where Custom Still Means Something
^This is a 1 inch gauge that shows your PSI. It is small enough to fit inside the stock.

And for every long magazine you have after the first, you should get this:
KJW M700 Constant Air Adapter [CAHWPP53] - $25.00 : Palmers Pursuit Shop, Where Custom Still Means Something

And this:
1/8"NPT Male Disconnect Nipple (for Back Check) - Airsoft Fittings - Airsoft

And this:
1/8 NPT Street 90 Elbow - 1/8 NPT - Air Fittings - Industrial

That sums up what you need to buy. Putting it together is all logical, too. Basically, cut the macroline to the size you want. Thats it. To release the push connect fittings, push the ring forward and pull the line out.

Before screwing in the fittings, be sure to add some PTFE (teflon) tape to the threads. Reference picture:

After the kit is assembled, you will need to drill a hole into your stock. Make sure the hole is angled towards the trigger so the tubing can go through freely. Your drill bit should be just 1/4 inch, and widen the hole a little bit.

So here is what your final setup should look like if you choose to go this route:

An issue that arising from having the regulator in your stock is that it rattles around because it is not a perfect fit width wise. This is a very easy fix, just add tape around the edges of the regulator. Just be sure not to tape any threads, moving parts, etc.:

And one final thing about this setup. Your butt plate, which your have pried off by now, has a good chance of falling off. I have had it happen a few times, and if you don't find it, you can't buy a new one without purchasing used or a whole rifle. To fix this, you can make a lanyard. First, you should be using string that is nearly equivalent to that on a ghillie suit. It must have good strength, and fair corrosion resistance. I have some left over sail ties so I will be using those in this portion of the guide. These are pretty good to use, they are waxed, thick and strong. Knots in these sailing ties do not come undone easily, so they'll do. If you do not have any of these laying around, you can use fishing string (usually greater than 6 lbs strength) or dental floss. What you will want to do here is create a noose. If you don't know how, Google is your friend. Some videos mention to make seven turns, but here we can use less, I used two.
Now you will want to unscrew the bipod stud mount in the stock. Put the open noose around the screw when it is through the stock. Pull as hard as you can and tighten the noose. Re-screw the stud and now you have the stock end of the plate retention:

Now you can go to the butt plate and drill a hole through the bottom end. Feed your string through the hole and create another noose. Now you should have a completed lanyard for your plate:

If you want an alternative to running your rig inside the stock but still don't want the HPA tank on your back, heres another way. You can take a rail of ant length and attach it to the bottom of your stock by drilling two holes into the stock to meet with the holes for screws in the rail. Now you can take two screws with nuts and hold the nut on the inside of the stock while you screw in the screw. Now that you have the rail secured to the stock, you can take a 30mm scope ring and attach it to the regulator (How perfect, the regulator's diameter is 30mm!). This will allow you to then install the regulator onto the outside of your stock. Here is how mine looked:

And here is how it should look when the rig is completed:

Using an HPA Tank
For those of you who want to use an actual HPA tank and carry it on your back, the necessary items are just about the same, but this link simplifies it. This will be the only thing from Palmer's that you will need to run HPA. It comes with the necessary products to run a full kit, but once again it comes with that pre-tapped chamber that requires the Tanaka Long Magazine. If you have the standard 10 round magazine, you can still use the below-linked kit, you just need to unscrew the brass fittings from the chamber and screw them into your tapped magazine.

You will also need to purchase an HPA tank: [url=] Airsoft Guns - Accessories & Parts | Airsoft Guns - BB & Gas | Airsoft Guns - HPA Tanks |

HPA vs. CO2

So whats the difference?
HPA (high pressure air) and literally just the air we breath compressed in a can. It is stored as a compressed gas and is very rarely affected by the cold. I prefer this system since CT can see below freezing temps and its easy to work with. I don't mind the tank or line.
CO2 is just carbon dioxide in a 12g canister. It is stored as a liquid, and can sometimes lose pressure due to cold weather. I stopped using CO2 in my stock since I continued to have the issue of liquid CO2 bypassing the regulator and bursting my gauges, macroline, and now my push connect. This is non existent in HPA. Another issue is that you got to reload the CO2 every 100 shots or so. In the stock, reloading CO2 is a slow and difficult process. If you go this route, be sure to change CO2 at a convenient time, and not when its required.

The next thing you will want is a new barrel. If you are coming from a VSR or other spring rifle platform, you may have heard of balancing you barrel to cylinder ratio. Great thing there is no need to do that on this rifle because it has no cylinder to get a value from. So forget that! We all know why upgrading to a Tight Bore is necessary and we've all heard the controversy surrounding bore sizes, but no matter, in the KJW anything is better. It comes stock with a 6.10 barrel, and yes, that decimal is correct. I started out with a 630x6.01mm barrel by Angel Custom. Why Angel Custom? Because they are cheap! If you have a lot of liquid assets (money), you may want to go ahead and contact EdGi for a quote on a Bull Barrel, or try a high end PDI. Those can cost you between $100 and $300 or something I believe, but the bull barrels are thicker and have less vibrations. So the Angel Custom barrel seemed like a good option- It's made of aluminum so it's lightweight, etc. I was wrong. I ended up going with a PDI Raven barrel later on, I liked it much better. But really, any 6.01 or 6.03 barrel should do.
If you are willing to experiment, try an ORGA Magnus 6.23 because that expanding CO2 can act like a Polar Star, so maybe the physics are the same. i don't know, personally I've never had the time or money to try it.

The KJW's outer barrel's inner diameter is about an inch, so you'll have a LOT of space between your inner and outer barrel. This can cause unnecessary vibrations in the barrel and make your shot do weird stuff. Oh no, what do we do? Barrel Spacers!

This is fairly straight forward, all you need to do is take some electrical tape and wrap it around in various parts of the inner barrel. This tape will act as a buffer between the inner and outer barrels, and it should also reduce those pesky vibrations that can throw off your shot. Your spacers should go from the tip of the outer barrel down to about 2-3 inches from your hop-up chamber (you will need this space in case you decide to mess around with the internals again)

The next thing you will want to upgrade is your hop up. To begin, get rid of you old bucking. While it is VSR compatible, its not very good. We'll get into buckings in just a minute, lets talk about nubs right now. The stock nub can be hit or miss, especially depending on your setup. If you'd like to go make your own nub, read on.
There are, again, two ways you can go with this. You can either have a V-Nub or H-Nub with a single mound bucking (Type A), or you can have a V-Bucking with a flat nub (Type B). Saying that neither your nub nor your bucking are deformed or imperfect, both setups should get you the same performance. The best bucking I have used for Type A's setup is a 9Ball Purple Bucking for the VSR. These are getting harder to find, but heres where I got it: Nine Ball VSR-10 Hop Up Bucking - Airsoft Atlanta Be warned, though, 9Ball is notorious for having left over casting rubber and such still on the bucking. Check your buckings before you install! Now you will need a V or H type nub for this. Why? The standard nub is very inconsistent. The diameter of the crescent shape it makes is too large to make it good. So, can I buy a nub? Nope! (As of right now you can't) You will have to make it out of a hard material. I chose PVC piping and cut it until I got a little chunk the size of my stock nub. Make sure this chunk is near a perfect rectangle or square. Now what you will do is you will take a fine-tip sharpie and mark the V-shape or H-shape you will be making. The V should look like two fangs and the H should look like the lower half of the letter H. Now you can take a metal nail file and file it until it looks like the shape. This will be the most time consuming, as you will need to install and reassemble the rifle and shoot. If the bb curves, you must take down your rifle again and file a little bit on the side that the bb curved to. Sorry for the lack of pictures here, my hands were too bloody after a "filing accident." With that said, only use an exacto knife if you REALLY have too :ashamed:
Making a flat nub is a much easier process, just shape your PVC into the correct size and make sure its flat. I just received my Angel Custom V-bucking, and while it is not my favorite bucking, the performance is outstanding with a flat nub. Using the V-Bucking with Flat-Nub will be the easiest way to make your hop up better
Here is what your V-Nub should look like:

And Flat-Nub:

Remember what I said, making one of these will take patience, as you will need to file it down precisely until it shoots straight.
Here is the idea behind the V-Bucking: The V shape the bucking has grips the bb on two different, yet even, contact points, giving the bb a consistent, centered backspin. The flat nub is just supposed to push down on the V-Bucking in a way so that neither fang of the backing is longer. The idea behind the V-Nub is basically the same, expect the nub is giving the contact points and the bucking is what is actually touching the bb.

There is one more thing we can talk about here, and that is doing a flat-hop modification to your bucking. This means removing the mound on your bucking, making it flat. When doing this, I used the stock nub, which seemed to give me the best performance. I found this way much easier to get performance from compared to making a nub.

While we are on the subject of hop up, lets talk about the Chamber Conversion Kit. A lot of people are looking to find one! I attempted to purchase one directly from King Arms in the UK, but 2 months later they said they didn't have it. Oh well. The truth is, you really don't need one, unless you own the Tanaka M700. This is because the KJW's stock chamber comes with the ability to use AEG and VSR barrels, which makes owning this chamber conversion kit redundant. Here's a picture for reference:

With that said, this entire kit is not 100% useless. As you can see in the picture, you've got more than just a barrel conversion kit. You will also find an increased performance nozzle for your bolt, a single piece hop up chamber, and an aluminum nub. However I still stand with the idea that it is not worth the $100+ to buy.
There are also several metal chambers on the market for the Tanaka that look like the standard KJW M700 chamber, but they will not work. They both lack the two small screws that secure the barrel and prevent it from moving. Unless you are very good with drilling and taping, and have a VERY small tap, I would suggest just staying with your stock outer chamber.
Here are the chambers I am talking about so you can AVOID them. Airsoft Guns - Accessories & Parts | Airsoft Guns - Gas Gun Parts | Airsoft Guns - KJW Pistol /Rifle Parts | Airsoft Guns - Accessories & Parts | Airsoft Guns - Gas Gun Parts | Airsoft Guns - KJW Pistol /Rifle Parts |

Still on hop up, lets seal up that bucking! If you've upgraded any gun, you may have wrapped teflon tape around your bucking and barrel to ensure there are no air leaks. Your KJW is no different. Heres a reference photo:

You can notice that here the barrel end of the tape there is a little slit. This is caused by the screw that holds the barrel in place, no need to worry here. Once you have done that you can put your clam shell chamber back together and reassemble. This just about concludes upgrading you hop up.

Theres another way to get around making your own nub. Yes, it is a little bit more expensive if done by a professional, but it works. There are many threads specifically for this, so instead of telling you everything, I'll give a basic overview and a few links.
So what is R-Hop? Its a custom fit patch that covers your barrel's hop up window. ER-Hop is the same, but the window of the barrel is extended, applying more hop up to heavy bbs. VERY heavy bbs. In fact, the design was originally for .88g steel bbs. ER-Hop in the case of field legal guns is generally overkill. Here are the links you will really need to know everything:

What you will need:
A barrel to R-Hop or ER-Hop
The correct tools (exacto-knife, files, sandpaper)
AEG-bucking (remove the mound)
R, IR, ER, or IER patch (Lets screw HS5, get this instead: McMaster-Carr and you get to pick a color)
HS5 ER-Hop Chamber (Shapeways, and this is not necessary for an R-Hop)
M-nub or EM-nub

Tony Zito is the ONLY certified Hunterseeker5 technician for R and ER-Hop. Again, SCREW HS5 :D
Why? Well, he screwed me… $200 spent for an ER hop and Tony's patch ripped in half after 2 days of use…
So again, get this: McMaster-Carr since its the source material for the tubing. It allows for hundreds of mistakes, where the HS5 z kit allows for three, and its also twice the cost. Did I mention you get to pick a color? :D

Now we can venture onto the bolt, yay! There are four upgrade components we will be looking at here.
To begin, you should purchase the G&G striker spring. This will increase the power behind your cocking piece and in turn make the firing pin hit the magazine's contact plate harder. This will push your gun to the maximum. You will also get a much more satisfying sound when shooting. Airsoft Guns - Accessories & Parts | Airsoft Guns - Gas Gun Parts | Airsoft Guns - KJW Pistol /Rifle Parts |
The next product is G&G's rubber set. Of this kit, you will only need one piece, and that is the one in the top left corner of this photo:

This part is more of a replacement, as its really only useful of you find air leaks between your bolt and the magazine. This is the only replacement on the market, so its good to mention. Oh, and it's a nice red color :) Airsoft Guns - Accessories & Parts | Airsoft Guns - Internal Parts | Airsoft Guns - Hop-Up | Airsoft Guns - Other Series Hop-Up |

Do you remember that the Chamber Conversion Kit came with a nozzle? You can buy it here: Airsoft Guns - Accessories & Parts | Airsoft Guns - Internal Parts | Airsoft Guns - Air Nozzles | Airsoft Guns - Other Nozzles |
This little guy should reduce air leaks between your bolt and your bucking. Disclaimer: This was made for the Tanaka, but since the KJW is nearly a clone, it should fit.I cannot promise it will fit.

And finally, there is the steel cocking piece by G&G. I would not recommend you buy this until your stock cocking piece breaks. This piece will need some modifying to fit, meaning you will need to file down parts to get it to spec. I've owned this part before, and G&G decided that their steel was going to be the hardest they could make it… With that said, it is very hard to file down. Airsoft Guns - Accessories & Parts | Airsoft Guns - Sniper Rifle Parts | Airsoft Guns - *Shop by Model | Airsoft Guns - M700 / AICS |
I previously owned a G&G G96, so most of the bolt's upgrades were taken off of that. How nice!

One last thing with the bolt is to take a file and shave down the bolt areas that seem to be "sticky" when you cycle the bolt. This makes for better weapon operation. You can also try to remove the casting seams, but theres not really a need if you're lazy.

Lets go to externals now. Many people want to know, is there a threaded barrel adapter? Yes, there is! However, is you plan on cutting the barrel like I did, this part will not work. If you will keep the barrel the same, here is the link: Airsoft Guns - Accessories & Parts | Airsoft Guns - External Parts | Airsoft Guns - Adapters |.

To use this, unscrew the two screws that hold the front sight in place. Then you remove the part that looks similar to the threaded adapter and replace it with the threads.

For those of you who want to cut you barrel so you don't have a 5 foot long gun when you use a silencer, you can still make a threaded barrel adapter. You can take this piece: Airsoft Guns - Accessories & Parts | Airsoft Guns - External Parts | Airsoft Guns - Outer Barrels | Airsoft Guns - Barrel Extensions | and put it in a lathe and begin to file down the outside until it fits in your KJW. Once it fits, you will want to take it out and put some electrical tape. This way you will need a hammer to fit it in the barrel (it won't come out now). Should look like this prior to installation:

After you have the threads fitted and installed, you may want a small rubber washer to act as a buffer between the barrel and whatever you attach.
It should look somewhat like this when it is installed:

Though if you have the tools/skills, or know such a person, I recommend making a threaded adapter and tapping the inside of the outer barrel.

So in that picture you can see I cut my barrel, thats because I didn't want a 5 foot gun. If you want to cut your barrel but lack the tools, I simply used a hack saw and a vice. It didn't take much to cut through and file until it was even.

One last thing to mention about the externals are the stud mounts for bipods. In The holes are just a tad bit small so you will need to drill them out with a bigger drill bit.

Whats so great about using a KJW M700 with all these upgrades? The power. Thats plain and simple. Unlike a spring rifle, you can now use heavy weight ammunition, still get enough power, and still have little stress on the internals. For example, I can use 0.43g bbs and still shoot around 600 FPS. The 630mm barrel in conjunction with expanding gases is a deadly equation for range. Your only limiting factor is your field's requirements.

And now that we are at the end of our guide, I just want to give you a list of brands that you should stay away from, I have used these brands and I can safely say no to them now.
1) Angel Custom (Buckings and stuff are all of terrible quality)
2) Matrix (Especially BBs because of how soft they are)
3) G&G* (*Not really a brand to stay away from, but use discretion when buying, as only some parts they make are compatible.)

And to give you a little inspiration, here's what my M700 looks like. Enjoy!

So that just about concludes my guide to upgrading your KJW M700! Thanks for reading! Again, I know a LOT of stuff about this gun, so if you have any questions or need clarification, go ahead and ask me :shot:

Almost forgot. The best part about this process? When this happens: *Player*: Where'd you buy that gun? *You*: I built it.

More to come!
Edit 1: Pictures work now
Edit 2: More added to bolt, gauge, and hop
Edit 3: Added another way to setup HPA rig
Edit 4: Added more to HPA rig, hop, silencers, bbs, scope
Edit 5: Added more photos to barrel spacers and hop
Edit 6: Added more to HPA rig
Edit 7 & 8: Cleaned up a bit
Edit 9: Added R-Hop and ER-Hop
Edit 10: Added some colors :D
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I've found out that boring the chamber nub hole to 4mm, and cutting one of those round pencil erasers to size, it fits perfectly. It's hard enough to apply force, and soft enough to not rip the rubber when shooting.
Hey M700 users, got a question for you.
Disassembled a friend's KJW M700 a few days ago and was impressed with the hop unit. Do I understand correctly that it has a sort of built-in TDC in it?
Exactly why I question sellers when they say their M700 has a "custom TDC"...
Does any of you have any experiences with the G&G plunger and knock arm?

I've heard increases of 50 fps, which isn't too bad.
Does any of you have any experiences with the G&G plunger and knock arm?

I've heard increases of 50 fps, which isn't too bad.
I'm not sure if it does, because those sort of things are for durability. Maybe if it releases air faster and in big volumes?
All that does is lets you adjust how long the valve is open for. (mechanical dwell)

I used one in my Tanaka AICS before trading it. That was a massive royal pain to adjust and set. It also had the tendency to go out of adjustment fairly easily. (at least mine did anyway)

I did not find it overly useful as you can achieve the same results using different means.

I have thus far been holding my CO2 rig in a pouch on the buttstock and have come to the conclusion that I don't like it. Unless it is situated perfectly it tends to get in the way of a comfortable firing position (rides forward and sits at or too near my wrist). I do, however, like the quick and convenient access to change CO2 carts when necessary.

Aesthetically, I like placement of the rig inside the buttstock. It also looks as though that setup provides for fewer things to snag as well. The down side in my mind is lack of convenient access to change the CO2 carts.

This leaves me to believe that the best alternative may be attaching the rig to the stock as illustrated in this guide. I think it leaves a little to be desired in the clean looks department, but does seem functional and provide convenient accesss to change CO2. Has anybody encountered any negatives to this method? Just wondering if it gets snagged easily on gear/ veg, or if perhaps there is concern with stability or ability to get into a proper shooting position. Thanks in advance.
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The down side with that route is that it can hinder bipod use in certain cases and angles.

Since the connectors are external, I would recommend using a barbed fitting and clamp rather than your standard push connect. Push connect fittings are annoying sometimes because if the tube is pushed too far in one direction, the o ring seal opens a little allowing for leaks... (massive leaks). When the CO2 is situated inside the stock, the stock housing keeps the tubing in place to prevent this, but since you want it outside, you should stick to barbs.

I personally think barb fittings hold the tube better, since the friction fit is much stronger than the push connect's barb hold. You can also get barb fitting to QD fittings from McMaster, this makes things easy.

The upside is that the regulator is always pointing up when firing straight, so the chances of liquid CO2 events are diminished.
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Hi everyone, I've read this particular guide for the first time months ago, and am now ready to start buying parts to get my build going. I'll be starting out with a KJW M700 Polic model. First mod that I want to do is Co2. I can buy a second hand 1/8 tapped long magazine (tanaka). From there, I have many options, but difficulty finding the desired sources.

I'm thinking of buying a Begadi Co2 Booster for this build; would that fit inside the buttstock?

I'm not yet familiar with snipers and/or gas replica's, as I've only worked on AEG's (and to some extent on GBB handguns) so far.

Any tips for the newbie? :)
Some tips:

Usually its easier for a new player to buy a JG BAR-10 to see if they like the role of the sniper- its not for everybody.

If you have your heart set on the KJW:

I have no knowledge of the Begadi thing, I use Palmers and its the best regulator I've seen for CO2 application, and it fits inside the stock.
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Some tips:

Usually its easier for a new player to buy a JG BAR-10 to see if they like the role of the sniper- its not for everybody.

If you have your heart set on the KJW:

I have no knowledge of the Begadi thing, I use Palmers and its the best regulator I've seen for CO2 application, and it fits inside the stock.
Alright! Thanks for the tip. I have actually previously owned a sniper, an ASG AW.308. I did not upgrade it, which resulted in the range being less than or equal to properly upgraded AEG's. Needless to say, it wasn't very enjoyable.

I do know that I want to have a sniper in my arsenal, as I enjoy filling different roles on the field every once in a while. I just need to make sure it's a proper one, so I can actually outrange the AEG's and make good use of it.

That's where this guide will come in. I'm fairly sure that the begadi one will also fit the stock. I'm aiming for that one because importing from the US is quite expensive for me (I'm in NL), and the dollar rate has gone up quite a bit compared to the Euro, so now it's more expensive than ever!

This is the begadi I'm considering: BEGADI CO2 Booster, with hose and valve for KJW / WE - BEGADI- Tactical clothing, airsoft, Outdoor and Accessories

When I have all the parts, I'll start tinkering and use your guide to try and get through all the steps. I might need to come back and ask for specifics.

Thanks for taking the time to write this up and answer!
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Over the weekend I cut down my outer barrel to accommodate a 430mm inner. Despite the great advice in this thread, I purchased the standard Tanaka/ KJW threaded adapter (example:
). For some reason I couldn't think clear enough to comprehend why this would fit in a longer barrel but not in a shorter one. As soon as I cut the outer barrel I immediately saw why. It is INCREDIBLY thick. I was stuck and didn't want to mess with returning the part, so I decided it was time to get inventive.

A 5/8" drill bit will bore the outer barrel out very close to the needed diameter. I found that first grinding some of the material away with my dremel gave a suitable area for the drill bit to catch and stay inside. It was a long and sometimes painful process as I was using a standard drill, no press available. Just take your time, lubricate if appropriate (I used WD-40 and it seemed to help). Once I achieved desired depth I did a quick test and found that it was just a little too snug for the adapter. This is nothing that a good whack with a hammer can't fix. Since I was using a SPR style flash hider, I screwed it on to the adapter to provide a flat striking surface and protect the threads. It is critical that you have everything aligned before you bring out the hammer. I thought I would give it a couple of taps just to see if it would work and ended up overcommitted with a spr style flash hider that did not have the vents properly aligned but was too tight to turn the asembly to adjust. I will probably just unscrew the flash hider a little bit and use the set screw to hold in place for proper alignment.

Let's caveat by saying that there is a real possibility that you could negatively impact accuracy due to lack of precision. This is "******* engineering" at best and does not meet the standards of what could be provided by a machine shop. For those of you who don't have access to machine tools or a shop or just lack funds, you can give this a shot at your own risk. It's an alternative to the method previously described with for SCAR adapter.
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The threaded adapter you bought can be used if it is machined, like you did.

I would have stuck it in a lathe to machine it down to size, then bored out the inner diameter to a slightly larger diameter so that the barrel doesn't touch it. The barrel spacers keep the barrel in line, the threaded adapter does nothing.

I like your "******* engineering" though! I know most people would have just returned the part.
I always knew my SCAR adapter wasn't the best, since it was a friction fit, made for those without tools *like me*...
It was a snug fit to get the inner barrel in, I am thinking that there are o rings that help hold it into place. Are you thinking that is not a good thing? (Wouldn't it aid in the same fashion as a barrel spacer?)
Eh, I only came up with that idea once you mentioned that the machining had to be perfect. If it isn't perfect, then I think my route would have been more forgiving, but if it is perfect then there should be an issue and act like a spacer.
Hey bobcat, great tool this!

Btw I'm looking to co2 rig my kjw m700 now, palmers (co2reg) have a "kjw m700 kit" with macro line, would this be any good? Looks like it's comes with all the stuff needed.

KJW M700 Macro Line Hose Kit

Thanks for the help mate, been reading the whole thread for a few evenings now :)
//Yep... thats everything you need. Some other things I would buy:

Mini Gauge, 0- 300 PSI - Gauges - Air Fittings - Industrial

This is because the gauge it comes with is 1.5", and the stock's largest width is maybe around 1.05". The gauge I linked is a 1", the one I use.

Make sure you have a stiff, sharp knife for that macroline... I used a hacksaw once...

Now I personally think that "package deals" are a bad thing. This is because it limits you to what you can and cannot do. I'm not necessarily a fan of Palmer's fittings and tubing. Their regulator and M700 adapter is great for our applications, but not much else.

I personally would have chosen to go to McMaster and found strong-flexible-<200PSI tubing. Then some QD fittings that use barbed fittings and not the push connects. They have a stronger hold and allow for a better bend radius.

What you have is fine, but there are different, better ways.
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Would it be possible for you to list what I would need for a hpa/c02 rig I'm based in the UK but fine to order from over the pond.

Thanks bobcat
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