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AAC's M4A1 (sopmod) build


aac

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Here my newest project, an M4A1 build (with Sopmod accesories)

Same as for my CQBR build, i wil try to make as much as possible parts by myself, purchasing separate gearbox parts, receiver etc...

I started with making a 14.5" government profile outer barrel, and A2 front sight base

 

This is how i started this project until this Specna SA-G01 crossed my path, an ideal base, so i revised my project.

I wil use most of the Specna parts, except for the outer barrel, frontsight, and flashhider. further i wil make some small accessories

 

So i wil go for an M4A1 with Sopmod accessorie kit, including M203 (already included with the Specna) icon_e_biggrin.gif

For the final result i would like to make a "battle worn" black upper receiver.

On a lower with a weathered dessert paint job, (necessary to hide the USMC logo on the magwel)

 

Here my reference pic's

seal.gif

IMG_3202.jpg

maxresdefault.jpg

maxresdefault.jpg

 

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The A2 front sight base

 

The Specna Frontsight base is nice and decent , but due to a more realistic weight i decided to make my own out of steel

It al started with a massive piece of mild steel

UqTyAc6.jpg

 

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M4A1 outerbarrel

 

The original Specna outerbarrel is ###### ! , dimensions not correct, finish not realistic, and to light

So a DIY steel version was required, i started with 14.5" government profile, until i "discovered" the

SOCOM profile, so i was almost "forced" to restart the barrel

 

The photo's are bit mixed up icon_problem.gif

JvkWVG0.jpg

 

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KAC M203 leaf sight

 

000_0011-5.jpg?t=1174118709

Here the original KAC M203 leaf sight

 

In my enthusiasm i forgot to make progress pics.

 

The Base plate

milled out of a piece of massive steel

nmTtanG.jpg

 

 

The various small parts

 

 

HXQezpP.jpg

 

Painted & assembled

 

PG2yTE2.jpg

 

After a few "tours" in A'stan & Iraq

 

The complete sight weathered with rubbing blocks, scotch brite

 

muDpxrj.jpg

 

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Upper Receiver assembly

 

The latest progress, the finishing of the upper receiver assy, sandblasted the parts, Fosco painted with various colors

to achieve a more realistic look, then i assembled the parts and, weathered the whole upper receiver

 

Click on the photo to see the complete album

llcglhi.jpg

 

The weathering job

 

Click on the photo to see the complete album

RYITvjY.jpg

 

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More later so stay tuned icon_thumbup.gif

 

 

Internals : The Gearbox

 

The newest chapter in my project; the stock Specna V2 gearbox requires -at least- a minimal upgrade-job , besides my first upgrade-job biggrin.png

In this case i attempted only to optimalise, the consistence, and overal functioning of the gearbox.

  • The brass cylinder was replaced by a Stainless steel Element version, i polished the inside (check here my Dutch polishing mod. topic)
  • I also did some polishing on the pitch of the gears, but if this wil yield better performance ??
  • The stock ball bearings performed remarkable lesser than the Element bearings i had (check the video below)
  • Finaly i did a shimming job (of coarse)
  • The Cylinderhead i replaced by an ALU Element version with 2 O-rings, and i also did a "Damper mod" wich corrected the AOE,
  • During the assembly i added some extra Loctite to optimalise the Airseal
  • Nozzle replaced by a SHS red nozzle
  • Piston, replaced by an Element multi steel teeth
  • Piston head replaced by an Element plastic silent head with ball bearing

Finaly everything greased & assembled with

  • Element "Airseal grease" for the piston & cylinder
  • PTFE oil for the ball bearings
  • SKF gear grease for the gears, and piston guides

 

Click on the image to see the complete upgrade-photoalbum

 

057kOLB.jpg

 

Internals : Hup Hup unit

  • The brass innerbarrel i replaced by this 6.03 Energy version from Airsoftpeak this one came in a Prometeus blister by the way ? :rolleyes:
  • The Bucking replaced by a Modify flat hop
  • The arm of the HU unit itself i "tightened" a bit with the help of some shims

Now only the testing is left biggrin.png

 

N7n1Kx3.jpg

 

 

Two new chapters added to my M4A1 project, the KAC 300M rear sight, and a weathering job.

 

KAC 300M rear Flip Sight

 

This time i choose the KAC 300M rear sight 1: Because its koosjer for this build, 2: because i didn't made this model yet, and i dont like to make 2 X the same piece :D

First some photo's of the original, real sight

 

uGmuQXk.jpg

 

The Baseplate

Once again milled out of a massive piece of mild steel

RLehXNi.jpg

 

The various small parts

I forgot to make photo's but there al made out of raw material, the "tower" is made out of stainless steel.

D0VkABL.jpg

 

Finally al the painted parts greased, fitted, and assembled

(click on the photo to see the complete album)

 

IR74jnG.jpg

 

And finally i did a small weathering job on the assembled sight

(click on the photo to see the complete album)

 

jviTHPQ.jpg

 

And mounted onto the M4A1

(click on the photo to see the complete album)

 

SyrbPwv.jpg

 

 

 

That's the last part i would made by myself so far, in this project :)

 

 

 

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The weathering job

 

Like i said in the beginning of my project, i wanted a heavy "battleworn" look on this replica.

This M4A1 should look like he as served for multiple years in the Afghan, and Iraqi dessert's

 

By finishing upper, and lower receiver in a different way, i want to simulate they are changed, and belong to a kit, (same as in reality appears)

 

The upper receiver is "supposed" he never was painted, but due to intensive service, the black coating is weared of so bad, that the bare metal starts to be visible, on the raised edges.

 

The lower receiver, and M203 are "supposed" to had a dessert camo paintjob somewhere in the past, but also due to heavy service the spraypaint is heavily weared off

 

Besides this technique allows me to camouflage the unrealistic USMC logo :rolleyes:

 

Finally the whole replica needs to have a "dusty" appearance, most of the time we see that Airsofters use a technique where they paint the entire replica in a Dessert paint, and then wash off the entire replica, leaving only some color in exces corners, and gaps, personaly i don't like this technique, in my opinion its to fake :no:

 

That's why i desided to use the so called "Pastel Dusting Technique" (well known by the modellers amongst us) looks waaaay more realistic ! :)

Its done with soft pastel chalks rubbed off with an X-acto knife,to a fine powder, and then added with rubbing alcohol, for adhesion.

 

 

 

Step 1: The unweathered lower on the weathered upper to show the diference, once again

(click on the photo to see the complete album)

LTekUA0.jpg

 

 

Step 2: Weathering of the black coating of lower receiver and m203, with abrassives, Scotch Brite etc..

(click on the photo to see the complete album)

ISEdxSJ.jpg

 

 

Step 3: Lower receiver and M203 are painted in a base coat of Fosco Dessert, and dusted with Fosco Mud brown

(click onthe photo to see the complete album)

eR2Qeft.jpg

 

 

Step 4: Weathering the Dessert coating with nail polish remover, dish wash sponge, Scotch brite etc...

(click on the photo to see the complete album)

Y3SYKVX.jpg

 

 

Step 5: Dusting the complete replica, with soft pastels, keep in mind that a rifle can be dusty, but is also kept clean by soldier, so make sure that the replica dont look like a plaster sanding machine :D

So this technique need to be added very subtle, so that there is only some dust in the "deepest" corners

FaFZNyu.jpg

aEtr7kP.jpg

SwpZukR.jpg

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The SOPMOD kit

 

SOPMOD stands for Special Operations Peculiar MODifications (check also Dutch/English guides overhere) and is how i wanted to look my project, when finished.

 

It are all Element items, and in fact its an (officious) BLOCK 1.5 kit, containing BLOCK I, and some items of the "BLOCK II phased increments", (like the ACOG with RMR, and 553 HWS) only the NV devices , and the Elcan spectre 1-4 are still missing .

 

XaYrGvM.jpg

hJ86Oms.jpg

 

And once again the original SOPMOD image for comparison

ENuckqH.jpg

 

And an additional photoalbum with some random combination pics (click here)

6Z1FyH2.jpg

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Goddamn, that's good machine work.

 

How do you bore out the barrel? Do you start with a steel tube or do you have a really long 8.7mm reamer?

Thx  :)

The barrel is made out of a plain rod, because i don't have a 8.7mm reamer.

  1. I pre-drilled with a long 9mm, drill ,
  2. then i drilled with 12mm at both barrel ends
  3. made 90mm long brass bearing and pressed in the bearings
  4. finished the bore with a 8.7 mm dril and polished the ID with #400 sanding tissue , until i had a nice sliding fit, with the innerbarrel, and without any exces clearance.
  5. The hop up slots, behind, are also adjusted in such a way that the hop unit as no exces radial clearance.   

J5CV1eA.png

 

  

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This is just exactly how it should be. It just hit me that your technical drawings are drawn by hand... So I am assuming everything was made on a manual mill and lathe too... This is not a "Project suggestion", it is a piece of craftsmanship. Art.

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Beautiful work there. Always wanted to build a SOPMOD kit myself in a nice Peli.

Yeah, such a Pelicase would be great, only think there  more expensive  than the replica, and accessories itself  :)

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