Welcome to my blog, the Gratutitous Gas Gun Geek. I originally started this blog to follow my attempts at building from scratch a WA M4, but it has since evolved into many other projects in the gas airsoft world. Watch me customize some airsoft replicas to look unique. I also do gas airsoft repairs and custom projects as well. Contact me for pricing and options!

Monday, October 1, 2012

Gas M4 Project #3 - The "Parts Bin" WE M4

If you belong to a few forums like I do, you find some incredible deals on parts, guns, and anything else you find.  I have been gathering some things for 'that project' or just whatever gun I feel like building.  Well, I have reached a point where it is a good time to bolt on and pin together an M4.  This gun will be a solid back up gun.  The WE M4 gas system is relatively cheap, and mags are plentiful now.  Purchasing an Open Bolt Kit gets you a good chunk of the internal parts to put together something nice.

So this project is made of parts I purchased for cheaper than usual, that does not mean it is crappy looking.  So far I have the lower receiver built up.  Here are a few pictures to kick it off.


















I had a WE receiver just sitting around that had the trigger guard pin tabs broken off in the back.  I just took a real steel aluminum trigger guard and JB welded it to the receiver.  It is already broken, and the new trigger guard was $5 at a gun show.  I could paint it to match a little better, but it isn't a huge problem in my opinion.

The stock is a real steel Magpul CTR Milspec stock.  It slides across a G&P 6 position buffer tube I got with another stock I bought for the CM901 project.  I am using a real milspec diameter tube for that project, so this spare buffer tube fit well.  It has numbers on the top, but they are covered up by the CTR stock most of the time anyway.  The friction lock is kind of pointless since the stock to tube fit is extremely nice and tight.  I replaced the standard stock ring with a real steel Magpul ASAP (Ambidextrous Sling Attachment Point) sling mount.  It allows a sling to freely switch sides as you change sides with your rifle.  It was a pretty cheap part, and can really enhance your AR platform.  I had to use the commercial tube spec pin in the ASAP to keep the tube from rotating when I tightened it down.  Not a huge deal, but I noticed the threads on the G&P tube were flatter and probably needed the slightly taller pin to fit better.

I have a real Magpul MOE-K pistol grip attached.  The design of the grip is to be even smaller than the standard A2 grip on the AR15/M16, while adjusting the angle so it allows the rifle to feel more comfortable tucked in close (commonly used for short barreled rifles).  The grip has a good feel with and without gloves, and fits right to the WE receiver with a slightly tight fit.

If you noticed in the pictures, I have some really big take down/pivot pins on the lower.  Those are real steel Yankee Hill Machine EZ Pull Pins.  They are designed to be larger for your hand to grab if you swap uppers often.  I used them here since I plan on keeping this as a back up.  I could swap the lower onto any rifle I want to fix an issue in the lower receiver for the day.  Who knows, maybe one day I will just build a proper upper for this as a nice addition to my collection.

The springs and detents for the selector switch and take down/pivot pins are for a real AR15 as well.  I bought them with a little repair kit I got at another gun show, and they fit perfectly in the receiver.  The selector detent needed to be filled down on the lip so it could clear the trigger box space to engage the selector.  Luckily, the WE selector switches are extremely cheap and work well enough.

Other than that, everything else is stock WE-Tech.  Trigger box drops in cleanly, and the buffer and recoil spring work well enough to nice recoil and rate of fire.  I have no complaints with this set up, and it feels good so far.  The most expensive part was probably the stock, as I only got it today and had to pay full price for it.  Probably everything together cost $250 for this set up, which isn't bad for a custom rifle.

This project will go by quickly so keep an eye out for a post about the upper receiver.  Next post will be a review, so keep on the look out for a really sweet rifle!

Thursday, August 16, 2012

Update #1B - Mailbox Ahoy!

Hello gas gun users, this is Quad G again.  Between the last post and now, I sold a few things I didn't need (like the closed bolt assembly I had and some books) and put the money to some good use.






To really give you some background, I have been debating over my WA M4 build.  It may have been the start of this blog in the first place, but it seemed like quite the expensive undertaking.  It could well go over $1,000 with all steel components and high end parts.  For someone at my stage of life, that is quite a bit of money.  With that being said, I have a bit of advice for those out there who want to endeavor on building gas blowback rifles:  Join multiple forums.

What sits inside of this package is something I got from a forum I mention a lot in this blog, Gas Guns Info.  This isn't about that particular forum though, I belong to a number of different ones.  You make friends with people by sharing the sport and similar interests.  Because of that, friends will help each other, whether it is advice for buying parts and accessories, or maybe something they are selling for some quick cash.  This particular package is because of the latter.





The guy I bought this from bought a G&P receiver set with a VLTOR marked lower, and a MUR-1 upper.  He really only did it to get the upper.  For some reason, the VLTOR MUR is a hotly contested item of desire for builders.  Probably due to the unique, angular style of its design.  Still, the guy wanted it for the upper, so he had the lower as a spare.  Not wanting it, he offered it to me for decent price.  I simply could not resist.













The receiver is brand new, and definitely looks good.  The finish is a little rough, but it is nice and even at least.  I do not think these are laser engravings, but silk screening.  What is nice about the G&P receivers is the pins are pre-installed.  The front one is done just like a real AR15.  Push in the spring and pin, slide the pivot pin in and rotate it until it clicks.  The rear pin is done by inserting the Take down pin into the receiver, sliding the detent and spring from the rear end of the receiver.  A small allen screw then holds it in place.  Normally, you would have to install a receiver extension or buffer tube with a stock end plate to hold it in.  This makes life a little easier when swapping stocks.  I won't plan on doing that since I'll have a few lowers to swap between.  Yep, I'm planning on making a precision (fixed stock) lower with a very light trigger and full auto disabled, and a standard carbine type lower with a durable trigger.  Not sure what this one is going to be used for, but time will tell if I find a good deal on some parts.  The only other complaint is the trigger guard, it rattles quite a bit.  Don't know what I'm going to do about that, probably swap it for something else.

Well, that is it for now, the start of  Project 1!  Gas Geek out.

Friday, August 10, 2012

Gas Rifle Review - WE-Tech M14

Besides building guns, I do have to buy here and there.  I used to run a Classic Army M14 Scout as a primary for 3 years before I got rid of it.  There was nothing wrong with it, but I wanted something different.  This is where the WE M14 comes into play.  Having seen video after video, I wanted one.  I've run it a few times (unfortunately with only one magazine), but my results are ready.  On to the review!

WE Tech M14




Real Steel History
Just briefly, I will touch on the history of this rifle.  The M14 was originally intended to replace not only the M1 Garand, but the M1 Carbine, M1A1 Thompson, M3 Grease Gun, and the Browning Automatic Rifle.  This would make a universal rifle to be used with logistics easy to take care of.  The problem was, it really only replaced the M1 Garand.  It was too light for the light machine gun role (the M60 obviously did it better), and too heavy for the submachine gun role.  It didn't see combat until the early stages of the Vietnam War, which was loved by troops.  The wooden stock would swell up and cause some accuracy problems, but the power of the 7.62 NATO was evident.  It was replaced by the M16 rifle in the 1960's, and at the time it was considered the shortest lived combat rifle in U.S. history.  In modern conflicts, the M14 has been given new life as a designated marksman rifle and semi-auto sniper system in the MK14 EBR and other variations.

Initial Impressions
The box the rifle comes in is lackluster.  It is cardboard.  There is not foam at all.  There are two pieces of cardboard that hold it in place.  The entire gun comes wrapped in a massive plastic bag, which is open at one end.  Upon lifting the rifle, you can feel the massive heft of it.  The plastic stock is colored to look similar to wood, and is rock solid.  You could probably beat someone to death with this thing if you wanted.  The grey color of the metal looks like a light parkerized finish.  The magazine has this weird green color to it, which kind of disrupts the look.

The instruction manual is pathetic.  It is literally the exploded diagram with all of the part numbers.  I personally think this is because WE secretly partnered with a few different airsoft reviewers, all of which demonstrated basic functions.  Seems like a cheap tactic.  The gun is already $350 ($420 for the Evike upgraded FPS model), so a proper instruction manual would have been expected.

Features and Components

Starting with the front, you can see the blaze orange tip.  It takes up most of the muzzle brake, but it does not cover the front sight (which I have seen on a few replicas happen).  It is held in by the famous castle nut, and a small allen screw underneath the front sight post.  I have not taken it off since I like the style, but I wish the orange part would have been smaller.  I guess it is more labor to mask off a part than paint the whole thing.



Next up is the gas block.  WE paid attention to the details quite well.  You can unscrew the front end, and remove a weak spring.  A fake,  metal piston will then fall out.  If you take the stock off and cycle the action, the piston moves in and out as well.  A neat little feature I must say.  The plug had a tendency to unscrew itself due to the recoil, so I put an o ring in it and it hasn't moved since.









Moving to the rear section of the gun, we have the butt plate.  It is hinged like a Vietnam era M14, and contains storage for small parts if need be.  My gun came with a speed loader, a small allen key for adjusting the hop up, and 30 round conversion for the magazine.  I swapped it in, so the parts you see are for converting the magazine back to 20 rounds.







Typical Garand style rear sight (which I love).  Elevation is extremely easy to adjust, windage not so much.  No trademarks or anything on the receiver, but RA-Tech makes a steel replacement  with markings.


 Interesting thing to note is the fact the bolt does not actually replicate the action like the real steel.  It only travels maybe 75% of the way to the rear.  This is because the real steel bolt tilts as it travels back into the receiver, while the WE M14 one does not.  There is however a rubber buffer at the back to cushion the bolt instead of allowing it to slam into the receiver.  The bolt has a cover on top of it that rotates like the bolt on the real steel, but the loading nozzle stays were it is and just travels rearward after blowback.









If you notice to there is a strange looking lever located on the right side above the trigger.  This is your fire selector.  You need to rotate it 180 degrees to switch between semi-auto and full-auto.  There is an 'A' stamped on one side, and need to be facing the stock when you want to use full auto.  All the lever simply does it shift the disconnector away from the hammer.  Full auto works well though.  I haven't had a single jam in the 1,000 rounds I've fired (Remember, this is a gas rifle, not an AEG).  The hooked bar is a full auto sear of sorts.  The hammer is held back until the bolt fully closes.  If this was not here, the hammer would just drop causing either premature gas expulsion or the firing pin would not have enough energy to open the valve and the gun would have to be cycled.  Simply removing the hooked bar and the selector assembly makes it a semi-auto only rifle.





Something I was upset about is the bolt catch.  It works fine, and I like it, but the button on the left side of the receiver is what irks me.  It works the opposite of the real steel.  Instead of pulling the bolt back and pressing that button to lock it, it does nothing.  If the bolt locks back after an empty magazine and new magazine is inserted, you can hit that button and release the bolt.  I have not done this to my rifle since it is asking for the catch to wear down.  I pull on the charging handle enough to release the catch, and let the bolt fly home.  RA-Tech does have parts to fix this and make it real steel functionality, but I would have personally liked it coming from the factory.


Disassembly is similar to the real deal.  Pull on the trigger guard to rotate the locking system open.  The trigger assembly simply lifts out, notice the spring stuck into the stock.  This is the trigger return spring.  If it falls out, make sure to keep track of it.  To continue the field strip, lift the action out of the stock and set it aside.  You don't need to disassemble further, as this is a very clean rifle for some reason (the real steel was, too).








The trigger is really nice for a GBB rifle.  The WA's that I've handled feel like they have 5-6 lbs triggers, which is accurate to the real steel factory trigger.  The WE M14 has a really smooth trigger.  I have not measured it, but it feels to be around 4 lbs and breaks cleanly.  It has a little bit of over travel, but doesn't have too heavy of a spring to really throw your shots off.  The trigger grouping looks very close to the real steel, disconnector and all.  The pins have a tendency to slide out when you move the parts outside of the stock.  I had to reassemble the magazine release twice because I was messing with it separate from the stock.  Just push them back in if you see them starting to move out.  The safety is typical of the Garand.  It clicks into place only when the hammer is locked back for firing.









The nozzle is plastic, but is housed in a metal bolt.  The nozzle itself does not rotate, but the top cover does.  As I said before, a rubber buffer prevents the bolt from slamming into the back of the receiver.  There is not roller on the hammer, so you can see the wear marks on the bottom of the metal.





The hop up adjustment screw is located on the right side of the receiver, directly underneath the auto sear.  This is not an ideal position, as the gun has to be disassembled partially to adjust.  No quick field adjustments for this gun.



WE apparently makes a nice low profile scope mount for this gun.  You can see it attached to the side of the receiver.  You have to remove the stripper clip guide to do it though, but luckily the mount comes with a pin punch to knock out the retaining pin.  The mount slides right in, and you have your choice between a hex screw, or the older style knob with a flat cut out.  Cost of this mount was $30, and I've only been able to find it overseas.  I have a Tasco 2-7x38mm scope mounted on high or very high rings.  You will need them to clear the receiver and rear sight.







Being a gas blowback rifle, gas is pressed into the magazine along with BBs.  If you do not have a speed loader to quickly and easily load, you can force them in by hand.  Be careful though, as I noticed that you need to insert them at an angle, not straight up or down.  The magazine fits 20, but using an included conversion it can be changed to 30 (more on that later).  There is not way to disable the bolt hold open on the magazine, unless you remove the pieces internal to its function.


It needs to be 'rocked' into the magazine well, like an AKM or FAL.  Since the magazine weighs close to a fully loaded real steel magazine, it might take some getting used to the weight.  The color does not match the rest of the rifle for some reason, and is the weird green.  It doesn't really matter that much, but would be nice if it matched the grey, parkerized look of the rest of the rifle.  The brass fill valve is in the bottom through the floor plate of the magazine.  The magazine can be inserted into the gun even when the trigger is pulled and the hammer has already fallen (unlike WA M4's).





The front locking tab is not fixed in place, so you could technically slide the magazine into the well.  I think this just helps the rocking motion should you not be perfect with the 'rock and roll'.  It does have wobble, but it locks into place once you get used to the way it locks up.


The magazine feels quite hefty since it contains everything to make it function.  This mag uses WE's split design rather than the stupid and horribly designed gasket mounted to the back of the magazine.  The o ring will be easy to replace or swap out since it held between the two pieces by two phillips head screws.  Simply pop off the floor plate, unscrew the phillips head closest to the front of the magazine, and slide out the internals, making sure you don't lose the two piece linkage to activate the bolt catch.  The magazine is originally 20 rounds, but comes with a replacement spring to convert it to 30 rounds.  Unscrew the screw near the top of the magazine (making sure not to send the spring flying across the room when you pull off the cover), remove the spring and a little black piece that restricts the round count.  Replace with the longer spring, and put the cover and screws back in.  All done.












Design Issues

Nope, you read that right.  I have a few complaints about this rifle.  They are short though, not too much to be honest.

First of all, the receiver has play in the stock.  You can shift it forward and backward about an eighth of an inch.  It does not affect the function, but it can be bothersome occasionally.  I have heard that with minimal modification, a real stock can be fitted, which eliminates the wobble.  I will be trying this at some point, hopefully with a VLTOR M1A stock, or a nice wooden one dated for the 60's.


Second, the trigger box will split.  That is right, not maybe, but will.  After around 1,000 rounds, my trigger started to break differently.  I pulled off the trigger group to discover the tan colored piece lifting off of the main, parkerized colored one (seen pictured below).  RA-Tech makes a steel, one piece (the other side still must be screwed on, but that part is already stable) trigger box for $100.  While you don't need it right away, be prepared to grab one at some point in the gun's life.


Thirdly, like stated above, the hop up is difficult to adjust on the fly.  Much like the TM designed M1911's, partial disassembly is required.  This is unwieldy for an 11 pound gun, but if you bench the gun to sight it in like you should, it is a minor inconvenience.  Set it and forget it.

Fourth, the upper hand guard is made of the cheapest looking plastic on Earth.  It does not match the stock at all, and makes the gun look cheap.  I believe real steel ones will fit with minimal modification, and I will be pursuing this as well.


Lastly, the stock itself.  While it does have a sturdy build, it is HEAVY.  There is supposed to be a weight buried inside of the plastic somewhere to add to the realism.  Add a scope and mount like I have, not to mention a bipod (it has a hole for the Harris style stud) and you have a 15 pound gun.  That gets tiring with a full kit of magazines to maneuver on the field.  At least the folding butt plate can keep it on your shoulder after a full day of running around.

Performance

So does this gun perform like older WE pistols and the Closed Bolt AWSS Gas System?  Nope, this gun rocks.  I got the Evike upgraded nozzle, which says it shoots 500 feet per second.  When I chrono'd this gun with .20 gram BBs, I was getting 495-525 FPS.  The standard version is supposed to shoot around 400 FPS.  This gun is built for hitting at long ranges.  With some .25 gram G&G BBs, I was getting 150 feet on a man sized target without even adjusting the hop up!  If you turn the hop up on, and use .30 gram + BBs, you will easily have a 200~225 foot gun with a stock barrel.  Barrel length is 22 inches, or 540mm.  I have no doubt you can have an extremely accurate gun if you swap out the barrel for a 6.03 tightbore.

Gas efficiency is surprising.  WE is known for having 1:1 or less in terms of having enough gas to shoot the entire magazine and lock open.  The magazine is huge, and gets 3 magazines off if loaded with 20 rounds, and 2 mags if 30.  This was test was done by firing 10 rounds in semi auto, then 3-4 round bursts until the mag was empty (waiting about 1 second between pulls of the trigger).  Cool down isn't too bad, but the mag can get chilly.

Recoil is like nothing else.  It did not seem to be as much as the WE M4 (which kicks around a lot), the M14 has so much mass moving around.  The kick feels like a .22 magnum.  The action cycling makes the sort of distinctive noise of the real M14.  Those who are familiar with the 'cling' of the rotating bolt and operating rod will know what I'm talking about.  The rate of fire is similar to the real one, around 650-700 rpm.  Full auto is not difficult to control, but will throw your shots off unless you are supported.

Upgrades

There are a number of different things you can do to your WE M14 to make it better.  Here is a simple list:

1) RA-Tech parts
RAT makes a steel trigger pack (selling all of the individual components as well), a steel receiver, real wood stock, and some other miscellaneous parts.  They also make a 'real function' bolt catch.  Two pieces replace the one part in the gun.  This can turn your bolt release into a bolt catch.  FPS can be adjusted using the standard WE NPAS made by RAT, but modifications need to be made to fit it.  RAT makes a conversion kit for the barrel and front sight to make your full sized M14 into a SOCOM16.  A 540mm 6.01 tightbore is available from them (also made of steel), and to top it all off you can buy a pre-upgraded version with the upgraded parts installed.  There are different 'levels', so you can determine your needs for upgrades.  Prices for complete rifles range from $600-$1,200.

2) VSR-10 Hop Up Buckings
You read that right, the hop up bucking in the WE M14 is the same as its TM compatible M1911 and its VSR-10 sniper rifle.  A stock replacement can be had for $10, but high end buckings can go for $30+.  Recent offerings include A+ bucking and REAPS bucking, which can extend the range another 100 feet reportedly.

3) Real Steel parts
I haven't tried this yet since my bills have been piling up lately, but reportedly a real steel M14/M1A stock can be fitted to the WE M14.  Minor filing may or may not be required.  The advantage of this is it makes the gun lighter.  The WE is not made of 100% steel, so WE made the stock to have some weight in it to bring it up as close as possible.  The real stocks don't have this and can save somewhere around a full pound or two of weight, that means less heft to move around and allows you to toss an extra mag in your kit.  A real wood stock and polymer heat shield also can give the gun a nicer look.  I've seen a few walnut stocks that look fantastic.

Those are pretty much the upgrades.  Ranging from cheap fixes to buying a second mortgage, your WE M14 can be tricked to whatever you desire.  There are a few things WE was supposed to offer, but still haven't come about in the two years of the guns release.  CO2 mags would make even higher velocities to come screaming out the muzzle and allow for colder temperature ranges of use.  WE has not really made a well built CO2 magazine, so I don't expect anything spectacular if it does get released.  The M14 is not the only rifle in their line up to not get a CO2 mag, the M4/SCAR is the only one despite promising ones for the AK after it was released.  WE has released an EBR variation that is official licensed by Sage International.  Two versions are now out, one with the sliding stock and adjustable cheek riser, and one with an M4 buffer tube known as 'Mod 1'.  Both are in the $400+ range if bought separately from the rifle.  A complete EBR is in the $700 price range.

Conclusion

So is this gun worth it?  Considering a basic load out of the gun plus 4-5 extra magazines can approach $500, this rifle is not an inexpensive venture.  That being said, if you are looking for something different to hit at longer ranges, this is the thing for you.  While it may not get used during winter time, when the weather gets above 50 degrees F this thing puts spring sniper rifles to shame.  Run heavy weight BBs and some green gas and you will have a good time.  Be prepared to drop some money though, the gun needs regular maintenance and some upgrading.  If you are not used to opening up guns and repairing them, don't start gas blowback rifles.  You will be paying even more for techs to do the upgrades for you.  The WE-Tech M14 is a great out of the box long range shooter.  While heavy in weight and cost, the gun performs well.  Add a scope, bipod, and disable full auto for a semi-auto sniper system that can compete with heavily upgraded bolt actions.

Thanks for looking into my review.  I hope it gives people a better perspective on this gun before buying it.  Gas Geek out.

Sunday, April 29, 2012

WE-Tech M4 Charging Handle Mod

The Gratuitous Gas Gun Geek has returned with a simple and really easy guide to improving the reliability of your WE M4 or M16 rifle, the Charging Handle Mod.

Background Information
The WE M4 is definitely a unique piece of kit.  As one of the cheapest GBB rifles on the market today, it is relatively cheap to get into the GBBR scene with something that will last enough.  There is a large number of replacement parts and a few upgrades laying around in retailers bins.  One of the more important things to take away from this is how close the rifle actually is to the real deal.  I will not mention too many specifics, but the way the mechanism is designed does not allow it to fire real rounds.

Since the quality of WE-Tech can be 'questionable' at times and the dimensions are close to that of the real steel, some of the parts can be replaced to increase the durability.  A common one is the charging handle.  The stock OEM (Original Equipment Manufacturer) part is a cast metal, most agree to be 'pot metal', which is not a strong way to manufacture a part that basically has to put up with being smacked around. The design is also bad because it puts a lot of force on the tip of an 'L' shaped piece, which puts a bending force on it.  To make a long story short and cut out all of the engineering junk, the front section of the charging handle will break off in due time.

The cost for a new replacement part is $15, which just so happens to be around the same price for a real, extruded charging handle.  If you have all the tools laying around, the only additional cost for this mod is $0.50 for some tension pins, easily making it worth it.  Real steel charging handles are made to withstand much greater forces, and for much longer.  Even though I used an extruded charging handle, the mod is the same for forged handles (usually these are slightly more expensive).

Tools Required
This mod didn't require a full machine shop, but some tools will make it a lot easier.  This is what I used:
- Hammer
- Drill Punch
- Cordless Drill
- 1/16 inch drill bit (titanium nitride coated)
- 3/32 inch drill bit (titanium nitride coated)
- 1/8 inch drill bit (titanium nitride coated)
- 1/8 inch diameter x 1/2 in tension pins
- Digital Caliper
- Stock WE Charging Handle
- Table Vise (and some wood to pad it)

You don't HAVE to have caliper, OEM charging handle, or the 3/32nd drill bit, but I have my reasons.  The caliper was used to get relatively close dimensions by comparing measurements, the 3/32nd drill bit was just another step for boring out the hole (more on that later), and the stock handle was for comparison purposes.  Everything else I feel is required.  You could even go one step further and use a drill press and a level for a perfectly vertical pin, but I think you can do pretty well with just a padded vise and a cordless drill.

The Modification
This is a very simple mod to do, but for those who haven't done something like this before, that is who I directed this guide towards.  If it seems like I drag on, you can skip to the titles of the sections.


1. Measurement of the OEM part
Using the digital caliper, compare the heights of the two 'L' shapes on the charging handles.  You will find the OEM part is a tad bit longer.  This is the only part you need to modify on the real one.  You can test this by putting the RS (real steel) one in your WE M4 upper receiver.  If it does not slide smoothly, then additional modification will be needed, but I have tested with 3 different upper receivers (all different versions) and found all three charging handles to run smoothly.  Please note that while my caliper is able to measure 4 decimal places, I rounded to 3 since it is really all you need to worry about.  This isn't going on the space shuttle for a trip to Mars.

Stock OEM part - 0.642 in

RS Extruded Charging Handle - 0.589 in

As you can see, there is a 0.053 inch gap to make up.  If you don't make up this difference, the charging handle can run into a plastic part of the carrier that was not designed to handle the stress.  You will see it on the Open Bolt WE M4's.  It is just a small plastic square piece that is bolted on to keep the loading nozzle in the carrier.

2. Put the RS charging handle in a vise
This is pretty self exclamatory.  The part you want to drill into is the lower piece of the 'L' shape, so this should be facing up.  You can notice from my set up in later pictures that I supported the charging in the vise with some small pieces of wood.  This helps prevent bending of the handle when you hit it with a hammer.  Wood is soften than aluminum, so the stress will be absorbed into it instead of your charging handle.  You want to tighten the vise so that way it does not move, but not so much that is warps or bends.  The wood also provides spacing the help with this, but the vise should be snug not tight.  Make sure you do not clamp the small parts sticking out from the sides of the charging handle.  Those are the guides that run along the inside of the upper receiver to keep the handle in place.  If you clamp that area too tightly, you will deform the handle, resulting in binding of the carrier.  Just make sure you leave that part out of the vise when you tighten it.  If you are unsure of how to set it up, look at the various pictures I have posted here and you will get the idea.

3. Mark the hole for drilling.
This I feel is a very important part, and why I used a drill punch.  For those inexperienced in machining and metal work, a drill punch is used to help guide a drill bit into metal.  Drill bits, especially when used in a cordless drill, have a tendency to 'walk' on the material.  This means you could line it up perfectly in the place you want a hole drilled, but the bit could drift to a different spot and begin the hole in a not so ideal place.  A drill punch solves this problem by marking a small indentation in the metal, right in the location you want.  Simply position the punch in the spot you want and hit it ONCE with a hammer.  The charging handles are made of aluminum, which is a soft material compared to the drill punch.  This means the dent is easy to make with a simple swing.  You can hit it more than once as long as it is in the same location.  You can tell when you have successfully punched the handle when you can run your finger over it and feel the indent.

The hammer in this picture is called a machinist's hammer.  It has replaceable end pieces made of brass and nylon fiber.  Unlike a steel hammer head, if you use a machinist hammer to hit something, the impact is absorbed into the hammer rather than possibly deforming your part.  For this, it is not necessary.  It just so happens to be on hand at the time.

This is the small dent I am talking about.  You can see the impression from the drill punch.  You want the pin to be close the edge that grabs the bolt carrier group.  I do not have exact measurements, but roughly a little lower than the middle of the charging handle.  There should be enough material to make sure the pin doesn't break through the end of the charging handle.  You are trying to mimic the OEM part remember.

4. Drill a 1/16th inch diameter hole
Again, this is pretty self exclamatory.  I used 1/8th inch tension pins for this, so why would you drill a hold smaller than the one you need?  There is a simple answer for this, the smaller hole is called a pilot hole for guiding the larger one.  Even though a drill punch was used to mark the spot, the 1/8th inch bit can still walk or drift.  If you drill a smaller hole first, then it is easier to have the larger bit drill the right sized hole in the spot you want to.  Aluminum is a soft material, so it doesn't take much to cut into it.
This it what it should look like with the 18th inch diameter hole.

5. Drill a 3/32nd inch diameter hole
This is just an intermediate hole.  I wasn't sure if the 1/16th hole would be big enough for the 1/8th to drill properly, so I used the 3/32nd to help bridge the gap.  I do not know if this was unnecessary or not, but I played it on the safe side.

6. Drill a 1/8th inch diameter hole
The tension pins are rated for a certain size.  I used 1/8th inch diameter pins for this, so they are actually a little bit bigger.  The way they work is because of the larger size, they put a force on the hole, which keeps the pin in place.  This may make it tough to hammer in, but they are very stable once in place.
This is what the RS handle will look like once its fully drilled out.

7. Hammer in the 1/8th inch diameter tension pin
Pretty simple.  You will notice there is a rounded edge on one or both ends of the pin.  Place that edge in first, making sure it is lined up with the hole correctly.  Take a normal, steel hammer (not a machinist's hammer) and begin hammering away.  A machinist's hammer is bad because the pin is made of steel.  You want to force the pin into the hole, not worry about whether you are going to damage it or not.  Just be cautious you do not slip and accidentally hit the handle.  It will deform.
You want the pin to be sticking out.  Remember the measurements that were taken earlier.  You want to try and get within 0.020 - 0.010 inch with this step.  You may need to remove the charging handle from the vise in order to measure it, and be prepared to measure it multiple times.

 8. File the pin to the correct dimensions
Once again, pretty simple.  Take a diamond coated file and shave down those last 0.020-0.010 inches off.  The pins I used were galvanized, which have a zinc coating on top of them to prevent rusting.  I'm not worried about rust since there is oil in the gun blasted out by the nozzle (if you use green gas especially).  Once again, this is a step you will be measuring quite a bit.  You are working for an overall measurement of between 0.064 - 0.066 inches.  Once you are done, clean up the shavings and dust with a paper towel (wet then dry).

 Pictured above is the kind of file I used.  It will take a few minutes to get the sizing correct, so be prepared to clamp and unclamp your vise.  If you mess up the pin sizing by taking too much off, just pull the pin slightly out of the hole and try again.  I highly doubt you will go through the full half inch length, so there is plenty of room to get it just right.

That is it, once you have verified you have the similar dimensions to the stock part.  Nothing else is needed to be done.  If you bought pins that have a black coating on them, you can touch up the area you filed with some cold blue.  Just make sure you know how to use cold blue, otherwise you will end up creating rust.

With the mod completed, you will need to make sure it fits properly into your WE M4.  I have what I believe is a version 1 upper and a version 3 upper, and I did not need to modify the handle at all.  I even tested it in what I believe is my friends version 2, and it still gave me no problems.  I'm not going to say your mod will be a drop in fit, but in my experience I haven't needed to custom fit the charging handle into a receiver.

There you have it!  A relatively straight-forward, simple to do mod for WE-Tech M4 patterned GBB replicas.  I have a new surprise waiting for the next posting.  I am just waiting for a few final parts to show up at my door.  The weather is warming up in Western New York, so let the plastic slinging begin!