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  

• For the ICS / CA MP5s and the TM MP5K / PDW

• For the TM MP5s and the UTG MP5

• Hopup / barrel change

• Structural problem 1: a weak front barrel mounting structure

• Structural problem 2: fore grip insertion

• Structural problem 3: fore grip wobble

• Structural problem 4: the SD suppressor and the inner barrel

• Structural problem 5: the MP5K inner barrel

• Structural problem 6: Hop Up adjustment lever wobble

• Structural problem 7: the grip and the motor plate

• Structural problem 8: high cap magazine reliability

• Structural problem 9: magazine wobble

• Structural problem 10: butt stock wobble

• Structural problem 11: battery compartment

• Special structural issue: MP5 parts breakage and replacement  

<< BRAND-SPECIFIC PROBLEMS OF THE INTERNALS >>

• A quick comparison of the current MP5 offerings

• TM specific internal problems overview

• ICS specific internal problems overview

• CA specific internal problems overview

• UTG specific internal problems overview

• Special UTG Technote 1

• Special UTG Technote 2

• Special Golden Bow Hybrid Mechbox Technote 

<< 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 and the UTG motor

• 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?

• Why should I replace the stock cylinder on my MP5K / PDW?

• 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?

• Do I need a metal body to sustain the upgraded power?

• 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 connector?

• 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?

• Can I use a Version 2 spring guide in a Version 3 mechbox?

• 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?

• 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?
  How do I hide the longer inner barrel?

<< TROUBLESHOOTING >>

• My stock TM MP5 is dead after 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 mechbox got stalled after replacing the tappet plate. What’s 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?

• 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?

• What needs to be regularly replaced to keep my gun in good shape?

• How about "Changing the Polymer Internals with the ICS Metal Internals"?

• Can I mix and match the receivers of TM/UTG and ICS?

• Is there a RAS kit available for the MP5K?

• Are the accessories for G3 and MP5 interchangeable?

Screen shots