Getting the mechbox out of a P90 has to be one of the most simple of all airsoft guns. Learn how to remove the version 6 mechbox from your P90. It’s dead simple. P90 provided by Airsoft Extreme.

A loose and constantly out of adjustment hopup dial is one of the most common and annoying problems with almost every brand of M4, M16, M733 or AR-series airsoft rifle.

If you have ever owned or used a M4A1 or similar AR-series AEG, you know how annoying it can be to have your hopup constantly losing its adjustment. I’ve tried dozens of field “repairs” including chewing gum, stuffing material under the dust cover and electrical tape – most of which only create a temporary fix. What I’ve done with my own M4 style guns:

The lock washer (or split washer) fix

My favorite fix is to find a small lock washer that will apply extra pressure to the hopup dial/wheel. I’ve used several types of washers and found that split washers do a great job of adding extra tension to the dial, allowing for a much more precise adjustment – that stays in place!

Replace it with a new unit

There are quite a few versions of replacement hopup units out there, so I can’t make a single recommendation for every version/model of gun. In some cases a replacement may be the right solution, but I would start with the washer fix unless you’re having other problems with your hopup.

Replacement hopup unit from Airsoft Extreme.

Metal hopup from Airsoft GI.

If you have some ideas or ridiculous things you’ve done to fix your M4/M16 hopup, leave a comment, I’d like to hear about it. -6mm

Learn how to rewire your M4A1 from the fore grip to a rear stock. This video includes a complete removal of the trigger, electrical components, selector plate and cutoff lever in a version 2 mechbox.

In this Mechbox Monday, we look at the basic toolkit and items you should have on hand before attempting to upgrade, repair or modify your airsoft gun.

This guide is primarily focused on the basic toolkit needed for beginning work on your AEG. Some specialized tools may be required for pistols and other airsoft guns.

Tools:

Most of you should be able to find the basic tools in your home, dorm, garage, shop or borrow them from a friend. Below is a list of the tools we recommend before starting any airsoft (AEG) work:

1. Screwdrivers (assorted slotted and phillips)
2. Allen/hex wrenches (metric)
3. Hook and pick tools
4. Needle-nose pliers (snipe-nose pliers)

Screwdrivers are fairly obvious, but these will help in disassembling the body and the internal components of the mechbox.

Allen or hex wrenches are essential for disassembling some AEGs and for adjusting motors. (Be sure the kit you buy has a 1.5mm Allen wrench).

Torx drivers are more specific to the Tokyo Marui (TM) mechbox, be sure to have a T10 torx driver if you’re opening TM mechboxes.

Hook and pick tools are really great to have for all kinds of situations. We regularly use the picks for releasing the anti-reversal latch, removing small parts, etc.

Needle-nose pliers are great for holding small parts in place or reattaching springs.

Miscellaneous:

Every job may require something specialized, but the general airsoft toolkit should also include the following:

1. Silicon lube (various weights)
2. Lube gel
3. White lithium grease
4. Multi-tool/knife

Silicon lubricants can be purchased locally at many hobby shops or online from most airsoft retailers. Make sure that you get 100% silicon, other oils can have adverse reactions with certain rubber components in airsoft guns. Silicon lubricants come in different weights (viscosities) for many uses including cleaning barrels, lubricating pistol slides and general magazine maintenance.

Lube gel is a great substance for lubricating the inner wall of the cylinder, tappet plate rails, air nozzle and the seals of the piston head. We also use lube gel to hold parts in place (like the head of a small screw). Superlube and Radio Shack lube gel are great alternatives to the Systema cylinder grease.

White lithium grease is a great lube for AEG gears, bushings and shims. You can find lithium grease in spray or tube, I recommend the tube form as it’s much easier to apply (spray lithium is really too thin and messy to be effective). Systema and others sell airsoft specific gear greases, we can’t find any obvious reason to pay more for them.

Multi-tools come in very handy and sometimes have just the right blade or other tool you’ll need when your mechbox is wide open and realize you don’t have the right size tip on your screwdrivers. Many times we have resorted to the Leatherman or Gerber multi-tool to get us out of tight spot during open-mechbox surgery. You’ll be glad you bought one anyway, if you haven’t already.

In closing:

There are plenty more tips that didn’t make it into this “essentials” list. Some other great things to have around are storage bins, even old jars or bowls to sort your parts as they are removed. Anything you can do to keep yourself organized will seriously contribute to a less stressful repair and reduce the chances of losing small parts. Stay tuned for more in-depth articles in the future including a list of spare parts we recommend you keep on hand.

Image used in header by: Schiller Garcia

Modifying an AEG can provide some much needed performance improvements, but what does this do for the life of your airsoft gun?

I’ve been told that just by opening a mechbox the chance that something goes wrong goes up exponentially. Why is this? Can I do anything to change that?

 

The short answer is, not necessarily. 

In fact, many times with the cheaper Chinese AEGs I have seen significant improvements to reliability after opening and upgrading the mechbox. Obviously, not all upgrades go as smoothly as expected and there is always a chance you’ll have to open it five more times to get it right. That does happen, even for someone that has performed the exact same upgrade hundreds of times before without a single problem.

Keep it simple. More is less, most of the time.

Some people have a tendency to want to replace everything inside the mechbox believing it will magically create the perfect weapon. In most cases, the more you add, the more likely you are to create new points of failure. The large number of manufacturers today who produce airsoft mechbox components also adds to the complexity of choosing parts that work well together. So, especially for people new to upgrading, I highly recommend starting with the basics (spring and bushings). More does not always equal better.

 

What, if anything, do I have to upgrade in my mechbox to support an M120 spring?

 

In my opinion, the following is required: 

1. Metal bushings.
2. Reinforced (higher quality) gears.

The most likely failure point with a stronger spring will be the gears or the piston. A wobbly gear (due to a loose bearing) can lead to stripping of the gears. The safe bet is to add the bearings and a set of new gears. Not all gears are created equal. Ideally, buy gears and bushings from a reputable manufacturer such as Systema, Guarder or Prometheus.

For improved performance: 

1. Ball bearing spring guide.
2. New piston and ball bearing piston head.
3. Consider a more powerful battery.

The ball bearing guide and head will allow the spring to rotate smoothly as it compresses and decompresses. A smooth rotation will reduce binding and twisting, giving the mechbox a slightly better ROF (rate of fire) and better durability. You might get a little more life out of the mechbox by adding a new piston. The fresh grooves on the piston will to mesh up with your new gears, again reducing the chance of premature failure after an upgrade. For most AEGs, the M120 will definitely slow the ROF and decrease overall battery life, so a slight increase in battery mAh or voltage may be necessary.

The key is to realize that everything is connected, so what starts out as a “simple” 400FPS (feet per second) upgrade can quickly become an expensive chore of adding more parts than originally planned. As stated in the first question, simple is usually better and more reliable. Something to consider before planning your upgrade.

Note: The M120 is usually fine for most mechbox designs, however the V2 box has some weak spots. Don’t be surprised if a fracture develops at the front of a V2 mechbox. There are some ways to prevent that, but I’ll save that for a future article.

Thank you to everyone who donated to the Mechbox camera fund. We’ve received and unboxed the new HV30 this weekend. Back to the studio!

Seriously, thank you! We’re excited to have the camera and ready to start capturing some new videos. As you can see in this video, I’m the guy opening the box of our new Canon HV30. We would have gone all digital, but we’re already invested in the lens, tapes, etc. that match up with the HV20/30/40.

So, this week, were going to fire up the lights in the studio and try to capture some new airsoft repair videos. Hot on my list are the version 7 box, a rewiring video for the version 2 mechbox and something more detailed about shimming the gears.

Thanks again. -6mm

This week’s question involves thread diameter and fitting a silencer to your airsoft gun. So, which way am I supposed to turn this thing anyway?

What size are the flash hider threads on Tokyo Maruis? I’m looking to make my own mock silencer, but I don’t know what size tapping bit I need to buy.

 

 

Most AEGs have a 14mm x 1mm (fine pitch) thread with either a clockwise or anti-clockwise rotation or pitch to the threads. So, it will either screw on using a righty tighty, lefty loosy method (which is clockwise/positive) or it screws to the left to tighten (anti-clockwise/negative). 

Each manufacturer has its own idea about whether to use clockwise or anti-clockwise, but I feel we can safely say that MOST AEGs use an anti-clockwise or negative 14mm thread. Tokyo Marui definitely uses the negative, anti-clockwise thread on its AEGs. In contrast, some guns have non-standard thread sizes like the TM SOCOM Mk23 pistol which uses a 16mm positive thread.

 

Just an FYI for those of you in the USA.

Technically speaking some imitation suppressors are subject to “legal issues” with regards to USA BATFE rules. I have ever experienced any issues with the use of an airsoft suppressor, but if you’re doing something stupid with an airsoft gun and it has a suppressor on it… you could be looking at some additional legal problems. This applies to homemade “silencers” as well.

A big thank you to everyone who donated or gave their support, we are truly grateful for the community support. The camera is on order. More updates coming soon…

Our trusty video camera recently died from some sort of electrical failure! We have several AEGs sitting and waiting to be shot, one of them we’d like to upgrade and give away!

We’re asking for your help to raise enough money to replace our camera. If you’ve ever saved a few bucks by watching our videos or you just like what we’re doing, please pitch in. So, click on the Make more videos! button and donate using ChipIn and PayPal.

Here’s what you’re helping us get for the Mechbox video productions to replace the dead HV20. We’ll be getting it from our friends at B&H.

After some research and digging around the web, I decided I could open up the camera myself (as it is well outside the warranty period now) to see if it was repairable. Using a few handy guides and some patience, I managed to get the camera open. I found the offending part that most likely caused the breakdown…it was the base of the tripod mount broken off and floating around inside the body!

Thanks everyone!
6mm

In our first edition of Mechbox Monday, we’re going to attempt to answer a few of the questions sent to us recently. Airsoft upgrades often seem complex and many times come with dozens of opinions about what works, what doesn’t and the cheap tricks that sound too good to be true. We hope to use Mechbox Mondays as another way to answer as many of those questions as possible.

A few airsoft repair questions:

How much barrel must you add to make a difference?

Longer is better…that’s what she said. I’m sure some will debate my reply to this question. In general, to have any real effect I think you need at least 50mm to gain noticeable improvements. For example, my personal TM Spetsnaz was upgraded from 229mm to the MC-51 285mm inner barrel with a little modification to the flash hider to make it fit. That extra 56mm was all I needed to tighten up my accuracy (relative to what it was before the upgrade). Remember, sometimes size does matter, but going too big can create its own set of problems – but that’s another story.

Does stretching the spring work to increase power?

Simply put, no, at least not permanently. Stretching the spring to be “longer” could (emphasis on could) temporarily give your AEG a slight boost in velocity. Even if it does give a temporary boost, it definitely will not last. Save yourself the hassle of having to open the mechbox again and use a new upgrade spring the first time. Not to mention, springs are one of the least expensive parts you’ll ever buy so just get one… and save the stretching for the skirmish.

Is thread lock really necessary on gearbox screws?

The short answer is no, thread lock is not absolutely necessary. The reason we demonstrate and recommend adding a small amount of thread lock is that we’ve seen what can happen when screws come loose. It’s not a regular occurrence, but a loose screw in your mechbox can lead to a premature stress fracture in the mechbox case. Our view, why not lock it?

Have a question of your own?

Send it to us and we’ll do our best to answer it directly or in one of our Mechbox Monday updates. Let us know what you’d like to see us talk about or video next!

In this video we show the disassembly of the version 2 mechbox and the installation of a new Full Tune Up Kit. This FTK includes new gears, piston, piston head, spring guide, spring, tappet plate, bearings and the necessary shims and grease to put it all together. FTK provided by Airsplat.com

Kitty at WGC sent us note to let us know about their new video of the modular gear set being installed in “5 minutes”.

The obvious advantage is not having to shim, align or time the gears – which is a major time saver especially for someone just getting started in repairing their own airsoft guns.

Since it’s YouTube and made in China, the quality is not great and there’s no talking throughout the video. I’ve asked Kitty and WGC to send us one of these modular sets to review and install, let’s hope they do!

This is a short clip of the assembly steps for the ball bearing piston head included in the Version 2 FTK Install video.

In the full version of video we cover the disassembly and breakdown of the version 2 mechbox (obviously). This FTK included new gears, piston, piston head, spring guide, spring, tappet plate, bearings and the necessary shims and grease to put it all together.

The shimming and gear alignment are explained verbally with some additional emphasis on reinstalling the trigger and how to assemble a ball bearing piston head.

From more than a thousand entries, we randomly generated 10 numbers using Random.org. We took those 10 randomly generated numbers and wrote them down with pencil on blank white pieces of paper.

We then put the 10 pieces of paper in my lucky boonie cap where I drew the paper with Rhonda’s lucky #654! Nice, nothing like a free AEG to make your day.

Congratulations to Rhonda from Gainesville, Florida for being the lucky winner of the Mechbox.com and Airsplat.com SCAR Giveaway!

See the list of the 10 randomly chosen entries below:

1. Alina, Florida, USA
2. Rhonda, Florida, USA
3. Tim Kendall (no address)
4. Oliver, Warwickshire, UK
5. Zelai, Bizkaia, Spain
6. Nicolas Beusen (no address)
7. Sebastian, Bayern, Germany
8. James Haggmark (no address)
9. Eric, New York, USA
10. Tibor Hoffer, Hungary

Thanks everyone for entering. Stay tuned for similar giveaways from our sponsors and from us here at Mechbox.com. Special thanks to Airsplat.com for making the SCAR Giveaway possible.

We’ll be working on the SCAR upgrade, along with the version 2 gearbox inside over the next month. Stay tuned.

6mm pulling the winning entry from the lucky boonie cap.

We just received a new P90 from our friends at Airsoft Extreme which we’re planning to do a “before and after” upgrade to catalog the exact results of a specific upgrade.  This month is going to be busy, but we’re planning to get a few things produced and out the door before September.

About the P90 video

In the first of what we hope are many upgrade videos to come, we are kicking off our first “before and after” upgrade with the P90 provided by AEX (Airsoft Extreme).  The idea is to demonstrate the exact results of upgrading an AEG including a list of the exact parts used in the upgrade, how to do it, tips and tricks and a link back to the website where you can order the exact same set of part to do it yourself!

The P90 upgrade will be a fairly complete overhaul including gears, battery, barrel, bushings, spring, piston, etc.

Version 7 mechbox video

We’re trying to get our hands on a set of basic upgrade parts for the M14 (V7) upgrade video.  We know it’s taking forever and hope to have some parts by the middle of the month.  Right now, the plan is to break down the AGM M14 mechbox and demonstrate a very basic upgrade to the spring (maybe the gears too). 

SCAR Winner

I’m sure many are anxious for us to draw the name of the winner.  Our goal is to see if we can reach a higher number of entries before we draw the winner.  Not only would we like more entries, we’re hoping to get some other videos shot before we commit to upgrading the SCAR.  Tell your friends to enter, post a link to the giveaway, blog about it…just send more entries this way! 

Thanks again to Airsplat (www.airsplat.com) for providing the SCAR for our videos and for this giveaway!  Drawing will be held on August 31, 2008.  A random number generator will choose the winning entry. Good luck!

That is all.
-6mm

A quick video of how to remove the barrel and hopup unit for the M14. We used the AGM M14 in this video, but the Tokyo Marui model is just the same. Includes a very quick overview of how to swap the bucking and barrel. M14 provided by Airsplat.com