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Mods To The Kjw M700 To Increase Consistency

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Mods to the KJW M700 to increase consistency (in FPS) and accuracy. Note-Consistency effects accuracy

I have included an estimated % of how much each of these mods effects overall accuracy

Free Mods:

Teflon tape hop up –Purpose=Consistency %2

Electrical tape barrel spacers-Purpose=accuracy %3

Tighten and loc-tite striker spring assembly –Purpose=consistency %7

Extend nozzle 1/16th inch by pulling it out of seat by that much –Purpose=consistency %5

Custom hop up spacer-Purpose= accuracy %5

Cheap Mods:

KA hop up bucking($15)-Purpose=Consistency %25

G&G, or KA striker spring($3-$6)-Purpose=Consistency(and upgraded power) %3

G&G rubber set ($13)-Purpose=Consistency %2

G&G Gas route Spring($3)-Purpose= Consistency %3

G&G or KA Plunger set ($15-$34)-Purpose=Consistency (upgraded power?) %2

High Performance Mods:

Tight bore barrel ($34-$75)-Purpose=Accuracy (this mod is useless if consistency is not addressed first) %13

HPA, or CO2 remote setup (under $120 for a DIY CO2 setup to $350 for a pre-built HPA setup)-Purpose= Consistency %30

 

 

There are a few of these mods that I haven't personally tested yet because the parts are on the way (ie KA bucking, I have the firefly. and some of the magazine mods).

However, I can tell you that once properly tuned with this equipment, and if you do your part, you can hit 12" groups at 150ft(because that is what I am currently shooting. hoping the airseal bucking closes the gap down to 6").

 

I will attempt to post an explanation of each mod in more depth in the days to come. There are actually a few different mods that I didn't mention because I haven't verified what they do yet. I have the takedown version, but the majority of these mods are exactly the same regardless of police version or takedown version. If you have a slight wobble in your takedown version, I'll show how to tighten that up too, so there is no play.

 

The majority of this information should apply to tanaka owners as well, with the exception that you will need the KA VSR conversion to accept the VSR barrels and hop up buckings, while the KJW already accepts these barrels and hop ups.

Edited by nodnarb

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do this fit on an KJW M700? http://shop.ehobbyasia.com/king-arms-chamb...t-for-m700.html

the text under says replace ur VSR-10 inner barrel to M700 barrel, but it fit tanaka M700 and M40. so do the Tanaka M700 got the Vsr-10 barrel stock or what do they mean?

 

and do this fit too? http://shop.ehobbyasia.com/king-arms-part-...ng-plunger.html

Edited by Timmeyh

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do this fit on an KJW M700? http://shop.ehobbyasia.com/king-arms-chamb...t-for-m700.html

the text under says replace ur VSR-10 inner barrel to M700 barrel, but it fit tanaka M700 and M40. so do the Tanaka M700 got the Vsr-10 barrel stock or what do they mean?

 

and do this fit too? http://shop.ehobbyasia.com/king-arms-part-...ng-plunger.html

 

Like I said in the post above, the KJW doesn't need the KING ARMS kit. They only need the bucking:

http://www.airsoftpost.com/king-arms-seal-...10-p-28401.html

 

I just ordered the plunger set for my magazine. I believe the internals of the tanaka and KJW mags are the same.

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Well I just installed my KA hop up bucking and G&G striker spring and OH MY GOODNESS it makes a difference! I only got to take 9 shots because I was doing this mod on my lunch break, but they made a HUGE difference in power(and seemingly in accuracy as well). I'm shooting Madbull .40s and they were just floating like .30s would before the mod. It added at least 25 yards to my effective range(75 feet or so). I'll report back later when I can sight it in and get a proper accuracy test. I'm running my HPA rig right around 100 psi or so, which is about the same as Green Gas pressure when it is warm.

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Most of the G&G stuff is for durability, not consistency. Since you haven't posted descriptions of the mods you have here theres no reason to not post the mods you didn't list yet. Some searching can also bring up links for each of these mods if you're looking to make a descriptive collection post. I'm interested in the "Extend nozzle 1/16th inch by pulling it out of seat by that much " mod mentioned, as well as your documentation and explanation for what it does.

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Most of the G&G stuff is for durability, not consistency. Since you haven't posted descriptions of the mods you have here theres no reason to not post the mods you didn't list yet. Some searching can also bring up links for each of these mods if you're looking to make a descriptive collection post. I'm interested in the "Extend nozzle 1/16th inch by pulling it out of seat by that much " mod mentioned, as well as your documentation and explanation for what it does.

 

Most of these mods will be linked to other sources as you mentioned. For a quick description of the "nozzle mod":

It seems the KJW already has an extended nozzle compared to tanaka's, so teh king arms nozzles may be useless. An extended nozzle simply pushes the bb farther into the hop up chamber so that it actually comes into contact with the nub of the hop up. This can help slightly with consistency as it puts the bb in the same place every time. Stock, the KJW nozzle seems to just barely get the bb into the hop up chamber at all, allowing the bb to either roll forward into the nub before the gas is released, or it will sit against the nozzle when the gas is released and have to "fly" pas the nub. I just took some pliers and gently pulled the nozzle out, and only pushed it back in 2/3 of the way. This gives the nozzle just a little bit more depth, and puts the bb right up against the nub.

nozzlebc2.jpg

 

 

 

 

In regards to the G&G Magazine mods: they do increase durability, but some users have reported more consistent fps after some mods: Airsoft Canada M700 A.I.C.S. post

Edited by nodnarb

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This post will show the tightening of the striker spring guide. It doubles as the installation of the striker spring.

 

Reciently I was getting inconsistent results and so I examined the bolt. I found the stiker spring guide to be loose enough that it was resulting in less spring tension. so I tightened it up and it shot better for about 1 magazine. I inspected it again to find it loose again! So now I secured the guide with thread locker,and it hasn't come loose since.

 

By the way, an upgraded striker spring can indeed improve consistency over the stock spring if the new spring itself is more consistent. The extra strength of the striker spring I beleive helps consistency as well, since it is striking the valves of the magazine all the way open, while I beleive the stock spring may not open the valve all the way, especially when there is high pressure. While using the stock spring along with an HPA setup, you actually have a saftey feature since the stock spring cannot release high pressures efficiently. So if you increase your PSI on your air rig to 150 for example, you will actually be experiencing REDUCED FPS since the valves aren't opening all the way. More on this some other time...

 

Opening the Bolt:

Remove the bolt from the reciever. remove the two screws on the bottom side.

boltdissassemblyis2.jpg

 

 

 

Remove the striker spring:

It is better to remove the striker spring by pushing down on the spring and removing the plastic spring seat halves. Now the striker spring will slide over the spring guide to be removed.

strikerspringdisassemblsc4.jpg

 

 

Remove, thread lock, and tighten the spring guide:

Start by pushing on the flat head side of the guide. The whole guide including the striker will slide out the back along with another small spring. Loosen the spring guide with a screwdriver(left side of picture) and use thread lock on the threads(where the nozzle of the thread lock tube is). Tighten it all back up and put the bolt back together in reverse order of dissasembly!

strikerspringguidejg4.jpg

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Remove, thread lock, and tighten the spring guide:

Start by pushing on the flat head side of the guide. The whole guide including the striker will slide out the back along with another small spring. Loosen the spring guide with a screwdriver(left side of picture) and use thread lock on the threads(where the nozzle of the thread lock tube is). Tighten it all back up and put the bolt back together in reverse order of dissasembly!

strikerspringguidejg4.jpg

 

You forgetting a step?

 

8xijow.jpg

 

 

 

 

Also, what did you use to secure the nozzle into place once you dislodged it from its traction setting? Nozzles are forced into place forming a "traction setting". Moving the nozzle in and out weakens the setting which has to withstand the 100psi+ worth of air now catching the backend "lip" of the nozzle. The King Arms nozzles are for eliminating tapered nozzles which make Japanese Tanaka's 1joule compliant. They are just a full bore nozzle allowing higher fps as opposed to the 300fps range mandated in Japan.

 

Sorry to correct you on this stuff but I've been giving out alot of similar info for a while now. If someone is going to compile a mega-thread I just want it done right.

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You forgetting a step?

 

8xijow.jpg

 

 

 

 

Also, what did you use to secure the nozzle into place once you dislodged it from its traction setting? Nozzles are forced into place forming a "traction setting". Moving the nozzle in and out weakens the setting which has to withstand the 100psi+ worth of air now catching the backend "lip" of the nozzle. The King Arms nozzles are for eliminating tapered nozzles which make Japanese Tanaka's 1joule compliant. They are just a full bore nozzle allowing higher fps as opposed to the 300fps range mandated in Japan.

 

Sorry to correct you on this stuff but I've been giving out alot of similar info for a while now. If someone is going to compile a mega-thread I just want it done right.

Oh brother. I didn't mean to bruise your ego. Have at it. You are more than capable. I saw your air rig post, it was excellent.

I just wanted to compile a list of mods that make the kjw better. Currently this info is scattered all over the net. I would love your input on these items, but I don't want to butt heads. Btw, the nozzle seats perfectly fine. You are barely pulling it out. I can't move mine at all without pliers. I do plan on eventually doing it right by getting some 6.5mm tube and making my own extended nozzle.

So, if I miss something, go ahead and add it or correct me. But if you want the preeminence, I'll just keep it to myself. Btw do you have a kjw or tanaka?

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Oh brother. I didn't mean to bruise your ego. Have at it. You are more than capable. I saw your air rig post, it was excellent.

I just wanted to compile a list of mods that make the kjw better. Currently this info is scattered all over the net. I would love your input on these items, but I don't want to butt heads. Btw, the nozzle seats perfectly fine. You are barely pulling it out. I can't move mine at all without pliers. I do plan on eventually doing it right by getting some 6.5mm tube and making my own extended nozzle.

So, if I miss something, go ahead and add it or correct me. But if you want the preeminence, I'll just keep it to myself. Btw do you have a kjw or tanaka?

 

Whoa, I want no credit. I'm not here to butt heads. I don't want to give you the impression I'm jumping all over you. If my post seem abrasive, then I apologize. This isn't about ego.

 

The KJW has had a bad rep for a while now, due to misinformation or lack of understanding. There has been a recent effort to show that it can be a 300ft accurate rifle through education and dispelling some of the bad info. So when you posted some good info but with a list with % quoting consistency along with a mod that hasn't been heard of before, it obviously raised some eyebrows. Your failing to mention the "set grub screw" (yours might be missing), which is a critical part of the disassembly process that would otherwise lead to a stripping of the striker spring guide rod also raised my eyebrows.

 

Details are important is all. If you had no problem resetting your nozzle then thats fine. But be sure to list that and/or a fix incase someone elses does not refit so well.

 

By all means, please keep posting. But if you miss a critical I'll jump in. I just didn't want to see a new owner strip their guide rod. Otherwise, I'll just keep quiet in my little corner.

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Whoa, I want no credit. I'm not here to butt heads. I don't want to give you the impression I'm jumping all over you. If my post seem abrasive, then I apologize. This isn't about ego.

 

The KJW has had a bad rep for a while now, due to misinformation or lack of understanding. There has been a recent effort to show that it can be a 300ft accurate rifle through education and dispelling some of the bad info. So when you posted some good info but with a list with % quoting consistency along with a mod that hasn't been heard of before, it obviously raised some eyebrows. Your failing to mention the "set grub screw" (yours might be missing), which is a critical part of the disassembly process that would otherwise lead to a stripping of the striker spring guide rod also raised my eyebrows.

 

Details are important is all. If you had no problem resetting your nozzle then thats fine. But be sure to list that and/or a fix incase someone elses does not refit so well.

 

By all means, please keep posting. But if you miss a critical I'll jump in. I just didn't want to see a new owner strip their guide rod. Otherwise, I'll just keep quiet in my little corner.

 

Actually I want your input. I don't have the time right now to write more in depth. Mostly I just wanted to discuss a few improvements that I haven't seen discussed for the KJW yet, and to share some information I've seen on other sites regarding things that I think most people miss. For example: the link to the canadian forum I posted which show fps readings after different magazine mods(G&G Plunger set, KM custom magazine part mod, G&G gas route spring etc...). This user was tinkering with things that I've never seen discussed before, and actually improving consistency with these mods. I thought it was worth a mention here, but not to re-create the post here.

 

To continue:

 

The Teflon mod is well documented for the JG BAR 10, but it is just so simple to show you what I mean with a picture!

 

Take your gun apart down to the barrel and hop up, and wrap the hop up with Teflon tape where it meets the barrel. (note, for the King Arms hop up, this is probably unnecessary since it has such a tight seal around the barrel, but it can't hurt. The firefly definitely needed it.) Try to warp it evenly. Some people have reported that wrapping it unevenly has caused the bb's to hook left or right.

 

teflonmodgc3.jpg

 

 

Electrical tape barrel spacers:

I didn't get a picture of this one, but it is straight forward. Take your barrel out, warp a small piece of paper around the barrel (just wide enough for electrical tape). Then wrap the barrel in electrical tape around the paper (the paper lets it slide). Do this until is just barely fits in the outer barrel. You will probably have to make it too thick, then slowly remove tape until it fits. Do two of these; one where the barrel tapers, and one right at the very tip just behind the orange tip. Alternatively you could use cork. Get creative.

 

You can tell by now that this isn't a detailed step-by-step guide. There will be not guide as to how to disassemble the whole rifle. You can figure that out yourself. This "guide" is just to give those who want to tinker with their KJW some ideas on how to improve accuracy.

Edited by nodnarb

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Tightbore barrel options:

I prefer the Dees Customs 6.01 mm PSG 1 barrel from airsoft gi. The DBC barrels are universally cut and don't require any modification to the barrel itself to fit the KJW with VSR style hop up.

 

The Madbull PSG barrel 650mm is available from evike or airsoft GI, and is a budget tightbore barrel that will work for the KJW. However it will need a groove cut around the circumfrence of the barrel for the hop up bucking to fit into.

 

Both barrels will require drilling out the orange tip to fit the slightly longer length of the 650mm barrel.

 

Some say the promethus barrel is the best even though it isn't as tight as the DBC barrel. It appears to be competitively priced with the DBC barrel on airsoft gi.

Edited by nodnarb

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In regards to the "Custom hop up spacer" mod:

The original mod for the police version is listed here: KJW M700 V-hop mod

 

The takedown version of this is the same principal, but different. Basically you want to make the depth of the spacer shorter so the grub screw that pushes down on it can get on top of it.(If you have a takedown version, you'll understand). I'll post pictures later of how the takedown version hop up works.

 

Note, if you get the king arms hop up bucking, I found that a flat spacer works better than the v-hop for some reason. Since the king arms nubbin is flat(or actually more semi circle), it doesn't need the v-hop like the firefly does.

 

This modification is custom in nature, so you should try a few designs to see what works best. but whatever you do, replace the stock spacer! The police version is terrible, and the takedown version is soft, making it more inconsistent with funky left/right hooks occasionally.

 

Edit: Here are some pics of how the hop up chamber looks on atakedown version:

dsc01781.jpg

 

dsc01788.jpg

dsc01789.jpg

 

 

Note the custom spacer in the third picture, next to the grub screw. It was an early design make out of a chopped off allen. It has a slight v- notch in the top. This worked OK for a while(before I got the firefly or KA bucking). However I learned it was rotating in the notch that holds it, so I made one out of some round metal dowel that was bigger in diameter than the notch, and flattened one side of the dowel so it couldn't rotate. My newest design for the KA bucking is just a flat piece of plastic that can't rotate, or pivot side to side in the notch since it is just barely able to fit and move freely.

Edited by nodnarb

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Nodnarb! So nice to see you again! This is Chris from FGA, otherwise known as Christafarion. Been a while...

 

Would you guys like to work together to do a thread like this? I bought a KJW M700 a while ago, and have been doing minor consistency mods to the air system. I think we could cooperate to prove the M700 can atcually be a good tinkerer's rifle.

 

Chris

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Nodnarb! So nice to see you again! This is Chris from FGA, otherwise known as Christafarion. Been a while...

 

Would you guys like to work together to do a thread like this? I bought a KJW M700 a while ago, and have been doing minor consistency mods to the air system. I think we could cooperate to prove the M700 can atcually be a good tinkerer's rifle.

 

Chris

 

So this IS you. I was wondering. What ever happened to FGA? I stopped airsofting for like 6-8 months due to work and personal life developments (all good), then the site was gone.

 

Thats awesome that you got the M700. Mine is shooting fantastic (Finally). It's nice to see the KJW M700 is finally getting a following. Even though it sucks stock, I actually think it can be as good or superior to a tanaka as an upgrade platform, Since it already takes VSR barrels and hop ups, and is cheaper overall. That reduces the cost of fully upgrading it by like $300 compared to a tanaka.

 

Let's definately work together. I don't currently have the time to put together comprehensive explanations of all the mods I listed, and I may be missing something others have done. I'm getting pretty tight groups since I finally got everything working properly. I'd say about 6-8" groups at 50 yards. I haven't had time for a proper accuracy test yet, but I will soon; by Saturday at least.

 

Good to see you again. How do you want to collaborate on the thread you want to do? PM works between two people, but we should include Brainplay. Should we use the remainder of this thread to organize another thread that is...well...more organized?

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I just bought the KJW M700 aswell plus nineball, KA and firefly bucking and an 630mm 6.01 ported EdGi barrel so il post the results later when im finished. just have to get it from HK first ;) takes a few days to norway.

Please do. I'm interested to see how the ported barrel performs. 630mm? I know the 650mm barrels are "too long" I thought the stock length was 639mm. It isn't much length difference, but I hope it still fits into the barrel tip insert. Would be a shame to have to shorten the outer barrel(or maybe not since it is quite a long rifle)

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Nodnarb,

 

Yes this is me, I kind of got a little forum face-lift. Changed my name, avatar, ect. I don't know what happened to FGA... I wish I could say more, but I honestly don't know. Terrk seems to have just vanished...

 

We could collaborate via this thread, then one of us could make a finalized one. I'd like to have brainplay on board first though, as three heads are better than two, and he's very savy with these kinds of pneumatics.

 

I have to go right now,

Chris

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I'd like to have brainplay on board first though, as three heads are better than two, and he's very savy with these kinds of pneumatics.

 

I'm here. I just need to know what you guys need for me to chime in. I usually only post informative or responsive stuff but I'm not real talkative on the forums. And I'll only really respond here or Arnies. I'm sort of boycotting ASR after getting a strike there for an infraction I didn't commit.

Edited by Brainplay

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I'm here. I just need to know what you guys need for me to chime in. I usually only post informative or responsive stuff but I'm not real talkative on the forums. And I'll only really respond here or Arnies. I'm sort of boycotting ASR after getting a strike there for an infraction I didn't commit.

 

 

We just need a list of every mod you can think of to increase consistency or accuracy. We need to then divvy them up, and each write a response to each one, or at least a link to a post that has the explanation(like your air rig post, which is excellent). For things like hop up buckings or tightbore barrels, we should post sources, prices and comparisons. etc...

 

It really shouldn't take too much time, at least to start.

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I'm here. I just need to know what you guys need for me to chime in. I usually only post informative or responsive stuff but I'm not real talkative on the forums. And I'll only really respond here or Arnies. I'm sort of boycotting ASR after getting a strike there for an infraction I didn't commit.

 

 

Same thing happened to me, but I just let it roll off my back like water off a duck's.. Even though Atilla's pretty strict, for the most part, he runs his forum like clockwork.

 

Let's start with this: Just a small bit of writing describing the KJW, and it's faults. If we can't identify it's faults, we can't compile information on remedies.

 

The KJW M700 is a gas sniper rifle. This means that it stores high-pressure gas in the magazine, and when fired, the gas is released from the magazine, into the bolt, and onto the BB.

 

There are a lot of problems with the KJW M700. Quite a few, to be honest. It's really a gun suitable only for someone willing to get into it's guts and tinker around.

 

We're assuming that [by reading this guide] you want the most accuracy possible out of your KJW M700, and you want to build it up to be a formidable sniper weapon. Also, we're assuming you'll spend your money, and even more of your time on this rifle. You could probably get away with buying a spring gun, and dropping upgrades into that to get similar, or better (or worse) results, but there's really nothing like the realistic action of a gas sniper rifle...

 

Let me be honest: In stock form, the KJW M700 is absolutely terrible in stock form. The only two things worth of note to it's name are it's incredible power, and relatively reasonable price. This gun can be found all over the internet for about $210 shipped.

 

So let me list off the KJW's problems:

1) Terrible velocity fluctuations

 

Say you're sniping someone, and the average FPS of your KJW M700 is 550 FPS, but it fluctuates +/- 100 fps. This means that the range of FPS your gun puts out is 450-650 FPS. You take aim at a target, and shoot. The BB fired is a mere 450 FPS, and it falls short. Luckily, the oblivious target didn't notice your first shot, and proceeds to pick his nose. Aiming slightly higher to compensate for the BB's short coming, you take a second shot. Your gun spits out this BB at over 650 FPS, and your shot blasts over the head of your opponent, skyrocketing off into the distance. Your foe notices you this time, and your cover is blown.

 

It's very important to have consistent FPS. In fact, it's the most important starting point for an airsoft sniper rifle. If you can't get consistent velocity, you can't have an accurate sniper weapon. Sorry, it's as simple as that. Now, the KJW M700 does have +/- 100 fps, as recorded by my chrono. The numbers were so all over the place, I didn't even bother to do a presise measurement- things kept changing. It's actually very frsutrating, really, but lets look at why this happens...

 

Firstly, The KJW M700 runs on propane, and it's stored in liquid state in the magazine. When it's release in the firing process, it changes into a gas, and rapidly expands down the barrel. This process is very inconsistent.

 

Secondly, the seal on the bolt, that connects the magazine's gas chamber to the rest of the gun isn't shaped properly to promote good sealing. A lot of gas escapes here.

 

Thirdly, there is a leak in the hop up unit. The seal between the nozzle and the chamber isn't airtight, and gas leaks out there as well.

 

Combine all of this with the masssively gapped 6.10mm ID barrel, the leaks add up, and cause inconsistencies. The first step for you to complete, is to make the gun spit out BB's at a consistent FPS. This IS the most important step, and IS the most involved.

 

Will continue after feedback,

Chris

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I love it. Great so far. I like how you've thought about this from the beginning, and explain how things work. I think people need to understand how it works in order to understand why a certain upgrade helps.

 

When you get time for more, just post it here. This will be the rough draft post, and someone can just compile all this information together when we finnish.

 

By the way, I just got in my new tanaka long mag yesterday and got a chance to use it. It does in fact fit snugly in the KJW, but this is because of the addition of another metal housing to cover up the rather weird looking magazine. Think of a notmal 10 round magazine, only with a really long feed tube that reaches down past the magazine by a couple lengths. Then picture two tubes that reach down to the bottom to increase gas capacity so it can fire all the 29 bbs. The shell covers all this up and makes the magazine just a bit fatter. Well, you can use it like this, but it can cause problems with how it seats into the reciever(sometimes too high, or not all the way in, and you cant really tell until it either drops the mag out because it wasn't seated properly, or it blocks the bolt because it is in too far.

 

So what I did was remove the outer shell to see how it fits. Well, it fits PERFECTLY and acts just like a normal 10 rounder, but looks ugly, and the feed tube is vulnerable. So I put the mag in again with the shell on, marked with a silver sharpie where it goes into the reciever, seperated the outer shell once again and used a dremel with a cut off wheel to chop off the top part of the shell. Now it looks great, and fits perfectly. Voila, Long mag for a KJW M700.

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Firstly, The KJW M700 runs on propane, and it's stored in liquid state in the magazine. When it's release in the firing process, it changes into a gas, and rapidly expands down the barrel. This process is very inconsistent.

 

Good post so far but one small mistake. The gas in the magazine is stored in liquid and gas states. The pressure is what keeps it in the liquid state while leaving a decent sized pocket of gas floating above (size of gas pocket is due to magazine chamber shape). When fired, pressurized but fully expanded gas is let through the valve. This causes a drop in pressure inside the magazine. The liquid boils and vaporizes into gas until the staturation pressure is attained. However, the vaporizing liquid causes a temperature drop. The body of the magazine retains the cold. The cold lowers the pressure in the magazine. Now instead of firing at say 95psi you're firing at maybe 93psi. Only 2psi difference and yet that can make a difference. Quick "strings" of shot continue to lower the pressure. But the body being made of aluminum will eventually warm to ambient temperature. Now your pressure is starting to spike as the temp in the mag goes up. Like a roller coaster, 95psi, 92psi, 94psi, 91psi, etc. This leads to the inconsistency for all gas rifles including gas bolts like the VSR series. Non-PCS Tanaka rifles suffer the same inconsistencies as the KJW in respect to the use of propane.

 

Summary: Gas doesn't expand in the barrel. Longer barrels will not help (tighter yes, longer no).

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Update:

Pictures of the modded long mag to fit KJW. This images shows the feed tube broken off(this is what can happen it you aren't careful). No matter. I glued it abck on with "Goat Tuff" and it is better than new. This glue is freakin strong.

 

longmagbrokenjd8.jpg

 

My newly updated CO2 rig. I tested this out today in freezing temperatures and it worked great!

 

co2rigaz7.jpg

 

Installed on Rifle:

 

riflerigjl8.jpg

 

An in game shot from today, just for the fun of it. Scored a 75 yard hit with two shots(second shot adjusted for windage).

 

ingameshotau5.jpg

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The KJW M700 is a gas sniper rifle. This means that it stores high-pressure gas in the magazine, and when fired, the gas is released from the magazine, into the bolt, and onto the BB.

 

There are a lot of problems with the KJW M700. Quite a few, to be honest. It's really a gun suitable only for someone willing to get into it's guts and tinker around.

 

We're assuming that [by reading this guide] you want the most accuracy possible out of your KJW M700, and you want to build it up to be a formidable sniper weapon. Also, we're assuming you'll spend your money, and even more of your time on this rifle. You could probably get away with buying a spring gun, and dropping upgrades into that to get similar, or better (or worse) results, but there's really nothing like the realistic action of a gas sniper rifle...

 

Let me be honest: In stock form, the KJW M700 is absolutely terrible. The only two things worth of note to it's name are it's incredible power, and relatively reasonable price. This gun can be found all over the internet for about $210 shipped.

 

So let me list off the KJW's problems:

1) Terrible velocity fluctuations

 

Say you're sniping someone, and the average FPS of your KJW M700 is 550 FPS, but it fluctuates +/- 100 fps. This means that the range of FPS your gun puts out is 450-650 FPS. You take aim at a target, and shoot. The BB fired is a mere 450 FPS, and it falls short. Luckily, the oblivious target didn't notice your first shot, and proceeds to pick his nose. Aiming slightly higher to compensate for the BB's short coming, you take a second shot. Your gun spits out this BB at over 650 FPS, and your shot blasts over the head of your opponent, skyrocketing off into the distance. Your foe notices you this time, and your cover is blown.

 

It's very important to have consistent FPS. In fact, it's the most important starting point for an airsoft sniper rifle. If you can't get consistent velocity, you can't have an accurate sniper weapon. Sorry, it's as simple as that. Now, the KJW M700 does have +/- 100 fps, as recorded by my chrono. The numbers were so all over the place, I didn't even bother to do a presise measurement- things kept changing. It's actually very frsutrating, really, but lets look at why this happens...

 

Firstly, The KJW M700 runs on propane, and it's stored in liquid and gas state in the magazine. The pressure is what keeps it in the liquid state while leaving a decent sized pocket of gas floating above (size of gas pocket is due to magazine chamber shape). When fired, pressurized but fully expanded gas is let through the valve. This causes a drop in pressure inside the magazine. The liquid boils and vaporizes into gas until the staturation pressure is attained. However, the vaporizing liquid causes a temperature drop. The body of the magazine retains the cold. The cold lowers the pressure in the magazine. Now instead of firing at say 95psi you're firing at maybe 93psi. Only 2psi difference and yet that can make a difference. Quick "strings" of shot continue to lower the pressure. But the body being made of aluminum will eventually warm to ambient temperature. Now your pressure is starting to spike as the temp in the mag goes up. Like a roller coaster, 95psi, 92psi, 94psi, 91psi, etc. This leads to the inconsistency for all gas rifles including gas bolts like the VSR series. Non-PCS Tanaka rifles suffer the same inconsistencies as the KJW in respect to the use of propane.

 

Secondly, the seal on the bolt, that connects the magazine's gas chamber to the rest of the gun isn't shaped properly to promote good sealing. A lot of gas escapes here.

 

Thirdly, there is a leak in the hop up unit. The seal between the nozzle and the chamber isn't airtight, and gas leaks out there as well.

 

Combine all of this with the masssively gapped 6.10mm ID barrel, the leaks add up, and cause inconsistencies. The first step for you to complete, is to make the gun spit out BB's at a consistent FPS. This IS the most important step, and IS the most involved.

 

^^ So this is all talking about FPS fluctuations. Maybe on more proofread? Anything to add?

 

Chris

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Well, Brainplay guided me to this thread because I was pming him about groupings that people were getting because in another thread brainplay said he had a lot of mods done to his. I'm just curious what grouping you guys are getting with certain mods because I'm really debating whether to try a KJW, gas bolt VSR. Igf this is a bad thread for this sorry, but I thought it might help for others as well to see what mods and upgrades can do for a KJW. Thanks.

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Well, Brainplay guided me to this thread because I was pming him about groupings that people were getting because in another thread brainplay said he had a lot of mods done to his. I'm just curious what grouping you guys are getting with certain mods because I'm really debating whether to try a KJW, gas bolt VSR. Igf this is a bad thread for this sorry, but I thought it might help for others as well to see what mods and upgrades can do for a KJW. Thanks.

 

Well, I still haven't done an official measured grouping with my KJW yet. I for sure know it is under 12" at 150 ft because that is the size of the target I was shooting at with these mods(and hit it every time). I suspect it is better than that though. I predict 6" at 150' but until I can actually measure the spread, I can't actually claim that. I know I am getting very reasonable accuracy and consistency at 75 yards. I've only shot that far in the wind so far, but I can hit a torso pretty easily. The 75 yard shot that I mentioned above (estimated distance, but I am a bowhunter and know distances very well, and on top of that, it dropped to my second mil dot, which is right at 75 yards) was a calculated and accurate shot. The first shot hooked left due to wind, so I angled the hop a bit to the right and moved the crosshairs a little to account for the wind, and fired again. I hit the opponent in the head.

 

I don't know much about the gas bolt VSR's, but to me it would come down to two things: weight(the VSR should be much lighter), and cost effectiveness(I don't know which would be cheaper because I don't know what mods are required for the VSR with gas bolt). From what I have seen of MOST VSR users groupings, my KJW is either on par or outperforming them, and I have no bolt pull effort. The cons to the KJW or Tanaka are the expensive mags(a 30 rounder is about $85 state side before shipping or tax!)

 

If I am not mistaken, guys who use the VSR gas bolt tap the bolt itself for HPA or Co2. This is kind of nice for practical reasons because you can use cheap magazines, and mag swaps are super easy.

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I just did the hop-up teflon mod, HPA rig and a firefly bucking and its working ok. but im getting the EDGI barrel tomorrow and then im gonna make the hop-up nub. so il post results later ;)

 

IMO the firefly sucks. It IS an improvement over the stock hopup, but the KA is much better for consistency. I was still getting fluctuating fps with the firefly. Now with the KA they are ALL right on target. No weird shots to account for and no inconsistent hop.

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Most of these mods will be linked to other sources as you mentioned. For a quick description of the "nozzle mod":

It seems the KJW already has an extended nozzle compared to tanaka's, so teh king arms nozzles may be useless. An extended nozzle simply pushes the bb farther into the hop up chamber so that it actually comes into contact with the nub of the hop up. This can help slightly with consistency as it puts the bb in the same place every time. Stock, the KJW nozzle seems to just barely get the bb into the hop up chamber at all, allowing the bb to either roll forward into the nub before the gas is released, or it will sit against the nozzle when the gas is released and have to "fly" pas the nub. I just took some pliers and gently pulled the nozzle out, and only pushed it back in 2/3 of the way. This gives the nozzle just a little bit more depth, and puts the bb right up against the nub.

nozzlebc2.jpg

 

 

 

 

In regards to the G&G Magazine mods: they do increase durability, but some users have reported more consistent fps after some mods: Airsoft Canada M700 A.I.C.S. post

 

 

im trying to get the nozzle out but it seems like its stuck. no matter how hard I try with the pliers its stuck.

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im trying to get the nozzle out but it seems like its stuck. no matter how hard I try with the pliers its stuck.

 

Be careful. Try a little twisting motion. Do not crush the nozzle. I don't believe it will come out easily if you try to pull straight out. I had to twist mine a bit while slowly pulling. If it is too difficult, I would forget about it for now. At least until you had a replacement nozzle for a worst case scenario.

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Here's a simple .txt file I made to compile all of the information on here. I've also labeled them as well. If there is anything else that you want me to add, just say so.

*=free mods

$=cheap mods

$$=High performance mods

**=mod tip/info

 

KJW_M700_mod_list.txt.txt

 

As well, what BB weight is ideal for the KJW M700?

Sorry for the necro post, It's just that this is a valuable thread for anyone who owns a KJW M700.

Edited by frapiscide

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The weights of 'the best bb' seem to vary on what gas platform you are using (Green Gas, HPA or CO2) but in mine, I have a CO2 system and I have noticed the right weight to accuracy ratio is .36's or .43's. I get far more accuracy with my 43's but I also have a few complaints from folks that take 150+ foot hits because they find it stings a bit. As it sits, I am shooting an approximate 530 fps range but thats approximate until the local shop gets another chrono that can read that fast. I compare mine with another spring sniper on my team, and his bolt was chrono'd in the same range with a madbull chrono.

 

I'd go with a .30 and higher to retain accuracy through brush and wind shifts.

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