KJW M4

[Raven1]

RANGE REPORT
Thursday, April 15th, 2010

1300 Hours

Gun State:

Magpul B.A.D. Lever - Cradle Airsoft Piston - Cradle Airsoft Aluminum Velocity Reducer - Using 'Echo 1' .28 BBs, Cradle Airsoft 6.03 Tight Bore 280mm Length for 10.5" CQB Barrel

Lower Now Machined To MILSPEC Dimensions!

Initial Inspection:

Bad News!  Initial Inspection of the gun revealed that I now need a New Upper Receiver!  It seems one of the ears on the upper decided to go south on me and the missing section is now where to be found! Some where in the Arizona desert I would imagine.

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Magazines Have Been Rebuilt:

Ordered and Received Parts - M1 - M7 - M9 - M12 - M14 and Successfully rebuilt each magazine.

Minus Replacing ANY Valves - The Valves themselves I am still evaluating and with the exception of having to re-seat the o-ring on the fill valve on magazine 1.
The magazines are working as normal.

AGAIN

Both Magazines are the Original Magazines Purchased with the gun!
Both magazines Have Only Been Lubed and Cleaned / O-Ring Has Yet To Be Replaced.
Both Magazines Have Been Deployed In Temperatures Ranging From 28F / -2.22C All the way Up to 118F / 47.7C and Are STILL Leak Free!

As Stated Previous: Lower Receiver Machine Work - MILSPEC Buffer

As mentioned in a prior post the lower receiver was delivered to my machine shop to have the Buffer 'Bore' machined to MILSPEC Dimension.

- Here is the side by side Comparison - MILSPEC on the Left

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MILSPEC on the Left


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MILSPEC on the Left


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MILSPEC on the Left



Assembly:

Was able to assemble the gun as normal with DSA MILSPEC Buffer Tube.
Encountered NO Issues with fitment or alignment of buffer tube to lower receiver.


Initial Functionality Test:

- With No Spring in the Buffer Tube -
- With No Buffer In the Buffer Tube -
- Gun Vertical / Straight Up ~ Down -
- Muzzle Pointed Down -
- NO Lube On Bolt Carrier Group -


- Charged BCG Back Half Way / Not Far Enough To Engage Bolt Stop -
Charging handle released and BCG returned to battery.
Repeated 10 X
Success 10 X

- Charged BCG Back To Bolt Stop & Hold -
Charging handle reset to home position,
MAGPUL B.A.D. Lever Actuated / BCG returned to battery
Repeated 10 X
Success 10 X

Satisfied there is no binding with a Dry BCG.
Satisfied there is No Alignment issue of rear Outside Diameter of BCG into Inside Diameter Buffer tube.


- Fully Charged BCG Back Into Buffer / So As Bolt Completely Disappeared Into Buffer Tube -
BCG Did NOT Freely Fall Back To Battery
Using Forward Assist BCG was "Walked" forward until it fell back into battery.


- Fully Lubed Bolt Carrier Group -

- Charged BCG Back Half Way / Not Far Enough To Engage Bolt Stop -
Charging handle released and BCG returned to battery.
Repeated 10 X
Success 10 X

- Charged BCG Back To Bolt Stop & Hold -
Charging handle reset to home position,
MAGPUL B.A.D. Lever Actuated / BCG returned to battery
Repeated 10 X
Success 10 X

- Fully Charged BCG Back Into Buffer / So As Bolt Completely Disappeared Into Buffer Tube -
Charging handle released and BCG Remained in Buffer
Keeping the Muzzle Down - and Shaking Gun Up~Down as if to shake water from it the BCG returned to battery
Repeated 10 X
Success 10 X


- Fully Lubed Bolt Carrier Group - Fully Lubed Buffer In Buffer Tube - No Buffer Spring -

- Charged BCG Back Half Way / Not Far Enough To Engage Bolt Stop -
Charging handle released and BCG returned to battery.
Repeated In Rapid Succession 10 X
Success In Rapid Succession 10 X

- Charged BCG Back To Bolt Stop & Hold -
Charging handle reset to home position,
MAGPUL B.A.D. Lever Actuated / BCG returned to battery
Repeated In Rapid Succession 10 X
Success In Rapid Succession 10 X

- Fully Charged BCG Back Into Buffer / So As Bolt Completely Disappeared Into Buffer Tube -
Charging handle released and BCG Returned To Battery
Repeated In Rapid Succession 10 X
Success In Rapid Succession 10 X


Will Evaluate Performance once the Heavy Summer Weight Spring arrives by post.
I Do Not have a buffer spring or I would have concluded the functionality testing today.

Sufficed to say if there is free movement free of any binding or fitment issue with ONLY the weight of the KJW BCG with a standard (Not Heavy Weight) buffer.
Also take into account the KJW BCG is No Where Near In Comparison to its WA / WE Counter parts.
It would be safe to conclude there will be no issues cycling the gun once there is a buffer spring to return the BCG back to full battery.

There will be ONE More Modification made to the Buffer so as to safe guard the Buffer Retaining Pin.
I will post up pictures of that modification once completed as well.

Thanks for your interest,,,


Total Magazines Expended = 0

1 BB Load To 1 Gas Fill

Total Issues / Incidents Encountered / Buffer Related= 1

Total Round Count = 13,264

[Raven1]

RANGE REPORT
Wednesday, May 19th, 2010

1700 Hours

Temperature 85F / 29.4C In Sunny Arizona -

Propane Gas Used - Coleman Propane Fuel

Firing Mode Rapid Fire Semi Auto & Full Auto Fire - 12 Magazines


Gun State:

Functional Parts:
Magpul B.A.D. Lever - Cradle Airsoft Piston - Cradle Airsoft Aluminum Velocity Reducer - Using 'Echo 1' .28 BBs, Cradle Airsoft 6.03 Tight Bore 280mm Length for 10.5" CQB Barrel - CLassic Army Redi-MAg - Lower Now Machined To MILSPEC Dimensions - DSA MILSPEC Buffer Tube, DPMS "H" MILSPEC Buffer, DPMS Buffer Tube Nut, "Summer" Weight Action Spring - Selector Machined To AMBI Selector.

Cosmetic Parts:
Magpul M.O.E. Trigger Guard - Magpul M.O.E. Pistol Grip - Magpul A.F.G. - Magpul M.B.U.S. - G&P Defender Front Set - MadBull Noveske KX3 - Magpul A.S.A.P. Plate - Element "Surprise Cock Fag" Dust Cover - EbayBAnned T-1 Replica w/Larue Mount - Magpul MILSPEC C.T.R. Stock

Complete Gun


Close Up Primary Side


A.S.A.P. Plate & AMBI Selector


Red-Mag & B.A.D. Lever


- Bolt Carrier Group Optimization -

The Cradle Airsoft Carrier Extension was rounded off to facilitate smoother entry into the buffer tube with no risk of sharp edges or flat areas that might positively contact causing a "Hard Stop" or sudden Binding.  



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The concern for the short term is Bolt Stop Integrity and the Long Term Concern are the Effects of the Added Weight + Stress on Bolt Carrier Group.

Initial Firing:

Rapid Semi Auto Fire
All rounds fired through to bolt locked back on BOTH Magazines.
Both Magazines Reloaded 3 X Each per Gas Fill.
32 BBs Per Load X 6 = 192 BBs
6 X Load to Bolt Stop = 6

Initially I was Most interest in this data as the concern was if the added weight would require more gas to move the Bolt Carrier Group to Cycle the Action Spring.

NOT The Case!  Both Magazines Demonstrated Typical Gas Management @ 3 X Reloads to 1 X Gas Fill.  Bolt Locked Back 6 X as expected, BB trajectory and shot placement and grouping was as expected.  No change in hop up performance or consistency.

The Gun shot and felt FANTASTIC - Nearly Twice The Normal Recoil!!

Close Inspection of Bolt Cup - Carrier - Piston had no unusual wear, areas showing signs of compression ( Being Smashed ) or stress cracks.



Dry Firing - Bolt Stop Test

Due to the added weight of the MILSPEC Buffer and the WA Summer Spring the concern is how will the bolt stop react.

Test Cycle to be repeated 30 X.

Fully Gassed Both Magazines -
Charged Empty Gun to Bolt Stop -
Loaded 1 Magazine into Redi-Mag -
Loaded 1 Magazine into Magazine Well -
Charged Bolt to Full Battery -

Test Condition - Travis Haley "Hyper Violent Manipulation"

  1st Cycle /
Pulled Trigger -
Bolt Locked Back -
Dropped Magazine from Magazine Well -
Quick Reload from Redi-Mag -
Actuate B.A.D. Lever -
Pull Trigger -
Bolt Lock Back -
Total Bolt Stop Captures = 2 Per Test Cycle

  2nd Cycle /
Pulled Trigger -
Bolt Locked Back -
Dropped Magazine from Magazine Well -
Quick Reload from Redi-Mag -
Actuate B.A.D. Lever -
Pull Trigger -
Bolt Lock Back -
Total Bolt Stop Captures = 2 Per Test Cycle

!!On the 6th Cycle Catastrophic Failure!!



Bolt Stop Resting on Magazine


As initially thought the added weight of the MILSPEC Buffer 85 grams over the KJW Spec 62 grams AND the Added Stress of the WA Summer Weight Spring was detrimental to the integrity of the KJW Bolt stop.

This Was to Performed 30 X Successfully!

The communication has been made to KJ Works for replacement parts, and did not feel the need to order another bolt cup as the damage to the bolt was to minor dents around the gas port and a long scratch of the paint on the carrier.


AGAIN
The Lower Receiver Is NO Longer Stock KJW due to the machine work performed for the MILSPEC Buffer Mod.

In preparation for the replacement parts the MILSPEC D.P.M.S. Buffer has had the appropriate amount of Tungsten weight removed to match the weight of the stock KJW Buffer.  Both Buffers are now identical in weight.

Not to be deterred and seeing where the Bolt Stop Break is located I decided to go ahead and gas, then load the magazines for another round of testing!
Why Not? What's A KJW If It Won't Shoot Broken - I Purposely Break My KJW So You Don't Have To!

Rapid Semi Auto Fire
All rounds fired with No Issues or Incident
Both Magazines Reloaded 3 X Each per Gas Fill.
32 BBs Per Load X 6 = 192 BBs
6 X Load to Bolt Stop = ZERO!!

2nd Close Inspection of Bolt Carrier Group - Found No New Issues.

Even in this condition I have Absolutely No Issues that the gun will keep running reliably or keep shooting consistently.

This pig will be skirmished this weekend I DON'T Care How Tired The Gun Says She Is!

So Please Expect yet another range report when the days AirBallin is done!



Thanks Again for your interest,,,


Total Magazines Expended = 12

Total Dry Fire To Bolt Stop = 11

3 BB Load To 1 Gas Fill

Total Issues / Incidents Encountered / Bolt Stop Related= 1

Total Round Count = 13,648

[Raven1]

KJW MAGAZINE UPDATE: Note - NOT A Recall - Again - NOT A Recall[/color]


I have just been informed by the KJW Factory that the Fill Valve Inner Brass Stem - The Long Brass Tube that screws onto the Bottom of the Fill Valve and Extends Into the Gas Chamber - Is Now Slightly Shorter Than Previous Versions!


1st Gen magazines have the L O N G E R Brass Inner Stem!

2nd Gen magazines Now Come Equipped with Slightly Shorter Stems.


This is due to TK and constant Optimization and Improvements of the KJW M4 - There is NO Reason To Change Out Fill Valves for this Reason Alone.  How ever when changing out these valves due to reaching End of Life Cycle then ( This Being Me and ONLY ME - IE: NOT KJW - But Me! ) I recommend replacing with the latest Revision of fill valve.  Just to keep the gun up to date and at it's most modern.


For those of you who are unaware the "Fill Valve" on the KJW M4 Magazines are The SAME Fill Valves that are used on the KJW M9 - Barretta Magazines!  Keep that in mind if you need a fill valve and need one quickly as your local airsoft retailer may have these valves on hand.

[airsoftguy01]

I'll add my recent dealings with the KJ M4 on Raven 1's thread.

Aug 24,2010: Acquired new 2nd generation KJW M4 CQB

Testing thus far as follows;

9x Mags with new 2nd gen mag = 0 failures to feed, 0 double feeds, 0 malfunctions of any kind

8x mags with 1st gen mag = 2 failures of feed, 0 double feeds, 2 malfunctions of any kind
 1st gen mag feed issue was a stuck feed spring, knocked the mag against nearby hard object and resumed shots as normal

Installed:

Magpul B.A.D. Lever
Surefire m900 Clone
Peq15 box
Magpul MOE Grip
CA Crane stock
OPS Inc 12th brake & collar
OPS Inc 12th Suppressor
PRI gas block/front flip sight


Notes: Magpul Bad Lever added after 3x mags, zero problems so far. BAD lever aids highly in clearing any possible malfunctions as well as making it very easy to manipulate the bolt stop without using reaction hand

MOE grip went on with zero problems. Some people have noted they needed to modify the selector detent area but no modification was necessary with my gun.

Modifications for the near future:
Cradle airsoft BCG extension
Cradle airsoft velocity reducer
Cradle airsoft piston
Milspec buffer tube mod
DD LITE RAS
Stanag mags
Ambi selector

Current state:

[airsoftguy01]

September 04, 2010

Testing Reports


Testing from last report:

21x 2nd Gen mags x30rnds = 630

10x 1st Gen Magsx30rnds = 300

Total rounds expended overall: 1,470

Failures to feed=1

Failures to fire = 0

In light of not being able to grab a velocity reducer from T_hum, Raven1 guided me (via text) making a velocity reducer by stacking several O-rings. $1.90 velocity reducer when you are in a pinch! However, for long term use, I suggest the Cradle Airsoft mod.

Internal Wear report:


Not much wear on the internals has occured since the first few mags.

The piston cup has been chipped since about the 10th magazine and has not effected performance and does not continue to chip. I applied some industrial grade polymer filler to keep the part from continuing to 'flake' off.


B.A.D. Lever installed.



Piston cup Damage


Buffer Wear


Hammer wear, very minimal!


BCG wear



Bottom of Bolt @ rear. This notch lines up with the buffer retainer and keeps the BCG from rotating

[uwanaugoda]

Sorry to bring ip an "old" thread but I thought it best not to start a new one. I have been looking to get the KJW M4 CQB for some time, but I cant really decide what GBBR M4 platform to go with. The problem I have with KJW is it dosent seem to upgradable, I really want the VLtor body and Bolt. Any one know if the bolt works in this gun?

http://www.ebairsoft.com/aluminum-bolt- ... -2597.html

[airsoftguy01]

Sorry to bring ip an "old" thread but I thought it best not to start a new one. I have been looking to get the KJW M4 CQB for some time, but I cant really decide what GBBR M4 platform to go with. The problem I have with KJW is it dosent seem to upgradable, I really want the VLtor body and Bolt. Any one know if the bolt works in this gun?

http://www.ebairsoft.com/aluminum-bolt- ... -2597.html

It's upgradable. Here is what it will take

AEG barrels with a $20 mod from Cradle airsoft
Cradle velocity reducers
Cradle carrier extensions
Cradle pistons
Cradle BCG
Most AEG and RS rail systems
AEG inner barrels machined by Cradle for $15

If you just want a GBBR because you want to watch the bolt reciprocate and have some kick, get something else. If you want a GBBR that is reliable no matter what, get the KJW.

The KJW is a masterpiece that works no matter what. Raven1 broke his piston cup and charging handle and played a game two weekends ago and had zero problems. These guns have been known to keep running no matter what you throw at them.

If you can find someone who has gone more than a few magazines on a WA/WE/AGM platform without some sort of issue than they are in the <1% of people that have.

yes, it would be nice to have after market body kits and stuff for this gun, but when you are out ranging all the AEG's and GBBR guys(when their shit works!) on the field, no one is going to care what your MBK looks like!

[BorderlandAirsoft]

Two questions!


Anybody know if these parts are compatiable with the KJW M4 and would it be better to go with the KJW or the New ATF approved King Arms M4? I'm leaning more towards the KA because it's cheaper, has a velocity and rof adjuster, and GI sells it with a pre-installed ris for $345.


-WE-Tech Nylon Fiber Reinforced Retractable LE Stock for M4 / M16 Airsoft AEG & GBB - (Dark Earth)
-Magpul PTS MOE Grip for WA M4 & G&P WOC Series Airsoft Gas Blowback Rifle (Dark Earth)
-Matrix 7" Free Float Full Metal Rail Interface System for M4 / M16 Series Airsoft AEG or Vector Optics Free Float RAS
-EA KAC M4 QD Silencer w/ SR16 Type Flash Hider (14mm CCW)