Want To BUILD my own M4, need help to start

[MP5HERO]

like the title says, i want to build up an M4 from scratch ( no, not buy an M4 and add new stuff, completely build it from the ground up.) but i have a few questions from anyone who can lend a hand and has some time. firstly, what are some of the best types of internals to purchase. i hear alot of people putting in systema internals but have heard nothing about systema other than their PTW series. secondly, to make it complete, what am i gonna need to purchase to have this thing running properly, and lastly, what are some of the best external parts to aquire?

p.s. would an mp5 gearbox work in an M4 body without modification.

p.p.s. is their anyone in WINNIPEG OR THE SORROUNDING AREAS selling these parts seperately, preferably for cheap? you know, extras and what not that you wanna get rid of. if you just ripped your stock motor or gearbox out of your M4 and dont wanna keep it, or replaced your lightly used folding stock and wanna get rid of the old one. that kinda thing. im not looking to buy a broken gun for hundreds of dollars that needs two tiny washers and its done. i wanna get to know this gun from the inside, out.

thank you for any help you can offer.

[theshaneler]

if you are not very mechanically inclined, i would just buy an m4 off some one, its not MUCH cheaper to build your own, a metal body will run you $200 at least.
some parts are hard to find, really just buy an m4 and tune it, its easier especially if its your first gun

[Groombug]

Originally Posted by MP5HERO

i wanna get to know this gun from the inside, out.

Buy a cheap M4 first, take it apart, fuck around with it, put it back together.

Once you're familiar with that, then you can think about scratch-building one.

[Qlong]

I ended up spending ~$350 for an M4 CASV build, this was with Chinese clone parts including Huang's black V2 gearbox, and NOT including the receiver + around 1 - 1 1/2 months of waiting for the parts / building.

[theshaneler]

if you are looking for a cheaper m4 that you can use and take apart, look at bob's retailer adds, if you are looking at higher quality more expencive stuff amos is your man, also the buy and sell area is great, give them a look see

[MP5HERO]

i guess i will take the advice of you guys.

[Shirley]

Well are you in with quality parts or cheap parts?

You can easily build an m4 because there are thousands of parts around you can buy.

Except, it's just hard finding, buying a metal body.

The rest, like a SYSTEMA gearbox and turbo motor is built for you.

Here's what I would do.

-SYSTEMA M4 Gearbox + Turbo Motor
-Any complete front end or you can buy hand guard, outer barrel, etc.
-Pistol Grip
-Stock - Full stock(no need for buffer tube)
Collapsible Stock (need buffer tube)
-Battery
-Inner barrel
-One piece hop up for metal body
-Two piece for TM bodies
-King Arms and G&P makes great metal bodies.
-DBOYS... depends how lucky you get if they fit or not

If the metal bodies don't come with furniture set, buy the ones with it.

Lastly, Accessories..
Front/rear sights, optics..


That's pretty much it.

[Shirley]

Also depends how much your budget is..

[simohayha]

i have build an m4 from scratch....and believe me, if u want quality parts, it WILL be very expensive and for me at least, its a pain in the *ss. u will need to do some filing and stuff since you'll be using 4 or 5 brands at least.some will "refuse" to work with other parts.
i need at least half a year to finally make it fully functional and reliable.(from listing and choosing the parts to completion). the hardest part of building an m4 from scratch (without any base unit) is to find those little and really2 hard to find parts like the safety catch (the ones blocking the trigger if the gun in on safe).if i remember right i end up buying around 28-31 parts to complete the gun.
here are the basic parts that i remember:
-metal body
-front set
-iron sights
-buffer tube
-stock
-grip
-magazine....lol
-outer barrel (if not included in front set)
-inner barrel
-metal hop unit
-hop rubber
-gearbox
-gearset,piston,piston head and all sorts of gearbox parts
-misc gearbox parts
-switch assy
-misc metal body parts (cocking handle,port cover,trigger,selector switch,and all sorts)
-motor
-a few deans and some soldering skill (most likely u have to make your own custom wiring,depending on battery placement and size among other stuff to consider)
-all other parts that i forgot to mention (most likely you wont get all the stuff from one store,even from HK)

but once u finished,it really worth all the trouble

[TokyoSeven]

Originally Posted by MP5HERO

like the title says, i want to build up an M4 from scratch ( no, not buy an M4 and add new stuff, completely build it from the ground up.) but i have a few questions from anyone who can lend a hand and has some time. firstly, what are some of the best types of internals to purchase. i hear alot of people putting in systema internals but have heard nothing about systema other than their PTW series. secondly, to make it complete, what am i gonna need to purchase to have this thing running properly, and lastly, what are some of the best external parts to aquire?

Lets start off with a few questions.
How do you want it to look?
What kind of front end do you want? Standard grip? RIS/RAS? MRE? Short?
What kind of trades do you want on the reciever? Colt? Special Forces? Blank?
What kind of stock do you want? Crane stock? Full Strock? Shorty Stock?
What is the time frame you want this project completed? Time frame can be a variable in regards to ones budget.

Now that you have the image in your head lets make a check list from front to back of externals components required. Feel free to copy and paste and then fill in what you decide as you go.

Front
Flash hider
OuterBarrel
Front sight/Gasblock
Front grip

Middle
Reciever
Grip w/motor plate and screws
Body Pins
Trigger Guard
Charging Handle
Mag Catch
Selector Lever
Bolt Catch
Rear Sight/Carrying handle

End
Stock Tube
Stock

Internals
Inner Barrel
Hopup unit
Mechbox
Motor
Battery

Lets talk about the mechbox for a minute, personally for myself when I did my own custom build I simply used a stock Tokyo Marui mechbox to start. Eventually a few of the internals were changed over to Systema with the exception of the spring which is modify. Recently though, all of the systema parts have been replaced with Prometheus parts.

If you are purchasing a prebuilt ready to drop in mechbox, be sure to consider where you want your battery storage to be, in the front or in the stock. Some people will recommend going with a prebuilt systema mechbox, however I found Tokyo Mauri to be just as satisfying even before upgrades.

In regards to your question about if you can or cannot use an version 2 MP5's mechbox for your M4, well you can but you will be required to change out the selector plate as that is designed specifically for the MP5 reciever and not that of an M4.

As for which parts to use, thats entirely up to you and your budget. For my build I ran exclusively with King Arms for all of my externals on my M4. However its understandable that sometimes its not with in a budget to use only one company. If possible, when it comes to your internals try to stick to one or two companies. When it comes to piecing your mechbox together, most people tend to agree that when building a mechbox its better to use all the same companies parts as they are designed to work together better. A

As for which parts are the best, unfortunetly I cannot say. If I were to say sytema internals where the top, modify users would disagree, if I were to say modify was the best, systema users would disagree. However from my personal experience with trial and error I found that both companies make quality parts for mechbox internals. There are many good companies out there that produce good parts. Look around online, do some research and you will see which ones are worth your time. Also, dont forget to buy the appropriate greases and lubricants for your mechbox as well!

If you are planning on building a mechbox from scratch I would like to make a suggestion as to what you could use for internals, I recommend going with Prometheus, do everything prometheus internally that you can afford to do.

From start to end on my M4 build it almost took an entire year and even today I am still toying and tweaking with externals.

Best of luck with your build, custom creations are fun and a great learning experience.