Airsoft Press Airsoft AEG M4 Gun Upgrade

Table of Contents

END USER LICENSE AGREEMENT

PREFACE

INTRODUCTION

GETTING READY

Tools you’re going to need
Proper handling of the screws
The proper ways of taking things apart and putting them back together  

PRE-UPGRADE HEALTH CHECK FOR NON-TM M4S

COMMON M4 ISSUES AND FIXES
TM specific: receiver pin tab breakage
TM specific: barrel wobble
CA specific: mechbox gear positioning and gear alignment
TM and CA: nozzle alignment
All models: body balance
All models: small pistol grip
All models: battery compartment for models without a fixed stock
Addressing the pin tab breakage issue (reinforcement and repairment)

PERFORMANCE UPGRADE

HIGH FPS UPGRADE
TM AEG: a baseline for performance measurement
What is proper usage?
What are the key elements of a high FPS setup?
Version 2 mechbox versus Version 3 mechbox: any difference in stock performance?
FPS increase in meter readings VS performance increase in a practical sense: the law of diminishing marginal gain in performance.
0.20g BBs versus 0.25g BBs versus 0.30g BBs: the heavier the better?
Does FPS always go hand in hand with Joule?
What is the difference between the FPS system and the Joule system?
How do you use FPS to measure Joule?
How do you use FPS to give an estimate of the range?
Higher FPS = lower ROF?
Softer spring = Higher ROF?
Harder spring = Lower ROF?
Is 8.4V insufficient for an upgraded mechbox?
Does battery size matter?
Is battery power important for semi-auto firing?
EG-700, EG-1000, ICS Turbo 2000, CA Super High Speed, Cybergun GPX5000 and other clones
Why (and why not) should I buy the high torque gear set?
Why (and why not) should I use helical gears?
Why (and why not) should I keep the stock plastic bushings?
Why (and why not) should I replace the stock plastic bushings with metal bushings?
What is an easy way to (more accurately) shim?
How do I tell if shimming has been done correctly?
What is the recommended order of gear insertion?
Longer spring versus shorter spring: the longer the better?
What are the major parameters of a spring?
Is a harder spring more harmful for the internals?
Installing a long spring: tricks and potential danger.
Installing a short spring: tricks and potential danger.
Why (and why not) should the spring be ground?
How to facilitate spring spinning?
What is a variable pitch spring? Is it always better for AEG?
Use of spacers for spring compression: tricks and potential danger.
What is wrong with a custom made spring?
Systema Springs versus PDI Springs
Can stainless steel spring offer better FPS?
Can Telfon Coated spring offer better FPS?
The long variable-pitch spring is very difficult to install. What should I do?
What can I do to reduce stress on the gears?
Can an EG1000 increase FPS (through higher torgue) over an EG700?
Why (and why not) should I use a Bore-Up Cylinder?
Different guns use different cylinders that have different number and position of openings. Why’s that?
Is it useful to block the cylinder opening altogether?
Why is it useful to put holes on the piston head? Any alternative?
Why (and why not) should I use a metallic piston head?
How about a silent head set?
Is aluminum piston more durable?
Is version 2 mechbox too fragile for M130 or above?
Do I need a heatsink motor plate on upgrade that involves M140 or above?
How do I effectively reduce heat on the motor?
Why (and why not) is the one o’clock gear timing an issue?
Can I still use the smaller batteries to power my upgraded mechbox?
I want to hide my battery inside the grip and the stock but the battery cells are too big. What should I do?
Chaining up your batteries: Parallel VS Serial configurations.
Should I use Sanyo battery cells for maximum performance?
How safe is it to remove the fuse? Any alternative?
Why (and why not) is it necessary to replace the stock wires?
Why is it necessary to shorten the wires? Can I use stereo wires instead?
Why (and why not) is it necessary to replace the stock Tamiya onnector?
Are NiCd batteries superior to NiMH batteries for driving upgraded AEG?
How do I optimize the overall performance of the stock motor?
Is it possible to increase the torque of the stock motor? If so, how?
What else should I buy for a high FPS configuration?
What is wrong with the soda can test?
What is right with the soda can test?
What is the most accurate way to measure FPS?

HIGH ROF UPGRADE
What are the key elements of a high ROF setup?
Can I increase the ROF while keeping the FPS at the stock level by using 9.6V battery?
Voltage VS mah – which one matters the most?
Can I increase the ROF by replacing the mechanical contact switch with a solid state switching mechanism based on MOSFET?
Can I increase the ROF by using capacitors at the power source?
Is high ROF a major cause of tappet plate breakage?
ROF-wise, why (and why not) should I replace the stock plastic bushings with ball bearings?
ROF-wise, why (and why not) should I replace the stock plastic bushings with metal bushings?
How about oil channel bushings?
Why (and why not) should I buy the high speed gear set?
Should I upgrade to a Teflon Cylinder?
How about a high speed cylinder set?
What makes a ball bearing spring guide meaningless for a stock TM gun? How to work around?
Is there any cheaper alternative to ball bearing spring guide?
Why a ball bearing spring guide alone may not increase the ROF?
Should I upgrade to an EG1000 for higher ROF?
How do I optimize the stock motor’s RPM without spending major $?
How can I increase the ROF while keeping the FPS at near-the-stock-level?
What is the right type of spring and battery to use for this purpose?
Is ROF over 30/sec possible?
What is the major ROF bottleneck?
Is aluminum piston better off for a high ROF configuration?
Are lighter gears better off for a high ROF configuration?
What else should I buy for a high ROF configuration?
Can I increase ROF by cutting off some teeth from the piston and the gears?

HIGH ACCURACY UPGRADE
What are the key elements of a high accuracy setup? Does a V-HopUp help?
How to improve accuracy with short barrel?
Can a long barrel deliver higher accuracy and range?
Why (and why not) should I replace the stock cylinder when using a longer inner barrel?
What is good about a high precision barrel?
How to maximize the effectiveness of a high precision barrel?
What is the drawback of using a high precision barrel?

TROUBLESHOOTING
My stock M4 is dead after approximately 3000 shots. Why?
What will happen with improper shimming?
And what should I do to remedy the problem?
How do I prolong the life of the mechbox?
When the mechbox is running, the nozzle does not move at all. What is wrong?
My gun stopped working in semi-auto mode. What’s wrong?
What cause the piston gear to break prematurely?
My EG1000 was overheated. What should I do?
What should I do for proper motor maintenance?
What cause the strange noise from the motor and/or the motor gear?
The two screws that attach the mechbox to the lower receiver are completely stripped. What should I do?
What causes gear stripping?
What can cause the hopup rubber to break?
I have to wind my hop almost all the way up just to get flat flight. What is wrong? 
How to prolong the life of my battery?
Is slow charging always good for my battery?
How to safely charge a battery?
Is NiMH battery free from the memory effect problem?
Should I fully discharge the battery every time after use?
How do I fix the battery memory effect problem?
My gun keeps mis-firing. How do I tell if this is a magazine problem or a mechbox problem?
I suspect that the hi-cap magazine is not working. What should I do to fix it?
What causes air leakage? What causes double feeding?
My gun makes an unwinding noise after full auto firing. What’s wrong?
How to take out the inner barrel?
What needs to be regularly replaced to keep my gun in good shape?
Can I use the ARII M203 unit on a TM compatible M4? Can I use the same on a Cybergun M4? Using M203 as your battery case.

Can I use the Korean Toystar M4 springer parts on my M4 AEG?
Can I use parts from a M4 springer to rebuild my M4 AEG?
Can I use parts from the cheap CYMA/Double Eagle M4 LPEGs to rebuild my M4 AEG?

SPECIAL TOPIC: CREATING YOUR OWN KITTY KAT AEG THROUGH SPRINGER-TO-AEG CONVERSION
Is springer-to-AEG conversion possible?
What are the steps involved?