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KJW M700P Build

72483 Views 94 Replies 31 Participants Last post by  ahp
I have been working on this gun for a while and wanted to share it with you all.

Gun: KJW M700P
Scope: Matrix 3-12x50 Illuminated Reticle Sniper Scope

Internal upgrades:
King Arms Air Seal Chamber
G&G Rubber Air Seal Set
CNC Chamber Conversion Kit
EdGI 6.01mm Precision Tight Bore Inner Bull Barrel
G&G Steel Cocking Piece
Palmers HPA Rig

External Mods:
Cut 5 inches from outer barrel
Custom thread adapter for 14mm CCW
10 inch custom silencer
Harris Bipod

Here is a test video I made today shooting it at the 200 foot range at Black Ops Airsoft, I need to tweak the camera mount a bit for tomorrows game:

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In the video I was shooting around 100 psi, I didn't chono it as I was just trying out the new bb's. When I first got the 0.43's I turned the HPA rig all the way up, i think it was around 150-160 psi and was getting 598 fps with 0.43 so it has a huge range (7.15 joules). Typically I skirmish with it at 500 fps with a 100 foot MED.
Shot of it in the case at the skirmish today, have some good game play video I am working on now:

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After putting it all together and using it for a few weeks its time to look around and see what we can make better. I noticed the bolt was a little sticky, and saw some wear marks. These are indicators that there is excessive rubbing going on.

When modifying your gun lets keep a few things in mind:

You are probably not smarter than the people that designed the gun. With that said you are not restricted by something they are, Time. Time is money in the manufacturing world, and they just cannot afford to take allot of time making and assembling your gun if they want to make any money selling it around $200.00.

You on the other hand can spend all the time you like taking it apart, checking tolerances, fit, and finish on all the pieces. The best way to do this is to use it, take note of parts that are too hard to move, to loose etc. Then take it apart, look for wear marks, and places to tighten things up. A good fit and finish check can go a long way.

As I was saying, the bolt is a bit sticky, and I can see wear marks right away:

There are also casting seams that can be removed, I only bother to do this on the parts that make contact:

Anyplace the paint is coming off is from wear, clean it up with some small files and fine sandpaper:

Remember these parts are cast not machined, so they are not perfectly flat and have flaws. Not because the people making them are stupid or lazy, it is about time and money. If the gun as all aluminum and cnc machined instead of cast and white metal, it would cost $2000.00 instead of $200.00. Use your Time advantage and clean all these parts up, don't try to remove metal, just do as little as possible to make the parts right and finished:

10 minutes later:

I cut off about 5 inches of outer barrel because I knew I would be using a silencer, and didn't want a gun 5 feet long:

This lets you see how much room is left inside the outer barrel even with an EDGI Bull Barrel which is bigger around than a standard barrel:

Since the inner barrel is only supported at each end it leaves the entire length unsupported and free to vibrate each shot. I made some nylon spacers to take care of this, I am sure you can buy these but they were easy for me to make so I didn't bother:

Here you can see why I chose the EDGI Bull Barrel, it is much thicker, and will vibrate less with each shot, only the ends are machined down to fit the gun still:

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Couple Pictures from the range today:

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Its a Plano Airglide, can get them from Walmart for around $35.00.
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Mine is pretty snug when sliding it in, I think a difference between the KJW and the Tanaka is the KJW has 3 set screws, two tighten into the barrel and one into the bottom of the hop chamber to keep everything super tight.

My hop bar was stainless steel and had very rounded edges, I wonder if they have updated the design, got mine from Evike in April.
Got my Tanaka Long Mag today, and sure enough it had sharp edges and a burr where the bb is pushed past to load into the gun. These sharp edges will score the bb and make it fly strange.

Arrow shows the burr:

After I smoothed the sharp edge and burr out with some 600 grit sandpaper:

I removed the fill valve and drilled/tapped the mag for the HPA (high pressure air) fitting:

QD fitting installed:

Hook it up and pressurize it, then dunk it in water to check for leaks, sure enough I had one:

A little Teflon tape and a re-tighten and it is good to go:

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I had a few of the fittings from some scrap lab equipment that I had stripped for parts (got it in an auction) and it had allot on pneumatic stuff in it. The fitting is awesome and swivels as well. Unffortunately I dont have a part number, you may be able to find something similar at a napa, ask the guy at the counter about air brake fittings.

The mag was hard to find in stock, but Airsoft Extreme had one and they got it to me fast.
I am using the stock hop bucking from the kjw, the G&G one that came with my kit was so tight the gun cannot push the bb through it!

With the upgrades I have done the gun is deadly inside of 200 feet, if the player is not moving much they are going to get hit. I feel like I can hit a person most shots at 250, but I can no longer pick where I want to hit them, the shot can go high or low or left/right a bit at 250 feet. Also at that range even a slow walk can make me miss because it takes a second or two for the bb to get there. I think it would be a wasted shot at this point beyond 260 feet. I may try it if it will not give me away but I dont expect a hit every time at that range.

I am using a Simmons Range finder to make sure I don't shoot inside my MED (100 feet) and don't try shots too long.

Very useful tool:
Been working on my burlap wrap for the gun. I was caught in the act by a field cameraman this weekend here:

This was a cool shot, the beginning of a LARP style game where I had to take out another player on command from my team lead over comms, shot went perfectly. It was 57 yards, and was a one shot kill on command.

great start to the day, and lucky for me the camera guy caught me all set up to take the shot from a second story window.

I will also be working on a kydex cover for the camera this week, so keep an eye out for pictures!
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At chrono they just mark my PSI and anyone can look at it all day and see it hasn't changed. Personally I think it would be harder to hit targets messing with the pressure all the time.
I started work on the Kydex cover for the Canon Vixia today. I need to armor this up a little as it was kind of expensive (for me at least) and I don't want it to get all shot up. I am starting on the view window face, since this thing sticks out and is a prime target for anyone that is shooting at me while I am aiming at them.

I started out by wrapping a piece of paper around it in the shape I want to bend the Kydex, then using the side of a pencil I rubbed the edges to get a good outline. Then I measured this outline, drew the shape in Inventor, printed it out and cut out the print to test the fit:

I tweaked the radius a bit on the rounded end, then sent the file out to the shop. Whipped up some G-code and cut it out on the cnc machine!

Here it is ready for some heat and a little bending to get the exact shape:

With some shape to it:

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Yeah I will be painting it, I have never worked with it before, I got this sheet from a guy that does make sheaths and holsters.
Thanks for that scrap of Kydex Boogeyman!

You can never assume a new part is just ready to install from the package. Here is a 9-ball hop rubber (which everyone loves to use) right out of the package. I installed it and saw a piece of rubber hanging down in the barrel, pulled it out and turned it inside out and found a bunch of casting rubber still on it, I needed to carefully remove the piece with a razor blade:

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I just stick a bit of each thumb into the hole, pinch it and roll it inside out. It is hard because the rubber is tough, but it is doable. This rubber is shooting pretty decent right now so I think I saved it, need to break it in and see what it does.
This is my custom thread adapter, it screws right into the outer barrel with a RH thread, and has LH threads on the end. I wanted something that would support the can very rigidly, and this fit the bill.

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Here are some pictures showing the drilling and threading of a Tanaka long mag for HPA. These are from a second gun I built identical to mine for a friend.

This shot shows the gas reservoir in the lathe with the fill valve removed:

The hole drilled out for the 1/8 NPT thread size:

The proper way to run a hand tap in nice and straight:

The threads all cut:

The reservoir cleaned up and installed back into the mag:

The nipple installed from the Palmers rig:

The Tanaka long mag is listed as not compatible with the KJW 700, but filing a little bit here and they slip right in:

Three styles side by side, from left to right: Palmers quick disconnect nipple, right angle air brake connector, old style twin reservoir Tanaka mag:

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1) When creating threads in the tapped hole, do you go "clockwise 90 degrees, counterclockwise 45 degrees" and so on until you reach full 360 degrees? OR until you reach the end of the threader drill?
What you are describing is called breaking the chip. As you turn the tap into the metal it cuts a chip that curls up on the cutting edge, backing it up lets the opposite side of each cutting face run into the curled chip that is still attached to the metal and it cuts it free.

This lets you keep the curls small and they wont clog up the tap and ruin the threads. Just go slow, keep it straight, and when you back it up you will feel it cut the chip and suddenly get easy to turn.

If it is a tapered fitting and tap I would run it in a little over half the threads on the tap and then remove it and test your fitting, if you can screw it in most of the way it is done. If not run the tap in a bit further and repeat the testing. You don't want the fitting to screw in by hand all the way, just most of the way, the tapered threads need to eventually get stuck as it is threaded in to create a seal.

2) You used a static drill, as far as I go straight perpendicular on the gas tank would you feel if I had no static drill close by? :) Hand drilling..done with multiple drill sizes from small to large..
This will work fine, just clamp the work piece down or in a vise so it doesn't turn or twist. Go slow, keep it straight, and use multiple drill sizes until you reach your desired hole size.

Don't rush the job, take your time, remember you cant put the metal back. The mag is expensive and you want it right the first time. If you feel the job is being rushed, or not going right, take a break and come back to it later.

3) What did you use to remove the gas valve? A simple flat screwdriver?
You can remove it with a screwdriver, just be careful. I used a valve wrench, you can see it in this picture (the Y shaped tool):

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I pulled on it a bit and it was in there tight so I did what you said and drilled it right out.
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