M4 SOPMOD airgun/replica

[FighterAce]

This is my recently finished M4...




With mounted telescopic bipod and suppressor... in the background you can see my zefal rush pump...

It operates at a pressure of 150 psi but the ekoplastik PVC airtank is capable of 290 psi. Its got a manually operated bolt system in witch the barrel moves forward allowing the bullet to be loaded, threads for mounting my homemade suppressor, functional wooden monolithic RIS rails for mounting optics, bipods, lasers, lights, ets. with the use of wooden mounts for it.
The barrel is 500mm long with inner diameter of 12mm - 1/2 witch is held in place with a 350mm long bolt. Hidden inside the wooden stock is a 3/4 green ekoplastik PVC airtank connected to a pair of ball valves. I fill the air tank using a schrader valve sticking out of the LMT stock. The first ball valve is a safety feature - it blocks the air so there's less chance of an accidental discharge. The second valve is the firing valve and its connected to a spring release mechanism with a self resetting trigger.
Its primary bullet is a nail dart (7cm long nail) with a paper cone. The magazine is removable and it stores 2 nail darts. It also has 2 sling points witch are waiting to be replaced with 2 metal carabinas.
The iron sights are homemade and they are both adjustable - front for elevation, rear for windage. The cheap red dot is just for looks and kinda helps in the dark.
Its pretty accurate at close range but I dunno for long range because I cant take it outside to shoot it because of its looks and the police roaming around. I used fir wood for the stock, the gun is just over 1.5kg and it took me 3 months+ to build it.

Hope you like it, cheers!

[rp181]

Fantastic! great replica!

What part is the air tank? Im guessing the small part in the stock.

[maverik94]

Wow! That thing looks awesome, juts like the real thing!!!! Any damage shots? By the way, welcome to spudfiles. 8) Oh, and also,

What part is the air tank? Im guessing the small part in the stock.

He already answered that for ya:

Hidden inside the wooden stock is a 3/4 green ekoplastik PVC airtank connected to a pair of ball valves.

[starman]

That's some really fine workmanship there. Very nice...really worthy of a shooting video and maybe some more construction details.

[rp181]

http://fighterace94.webs.com/
if no one has seen it, he has a bunch of awesome replicas.

[ramses]

That looks incredible! My only suggestion would be to get real aluminum rails and screw them on. They would be more accurate for mounting, would wear better, and would be more dimensionally stable with temperature and humidity.

At first, I thought you had gotten an airsoft m4 body and replaced the innards. Upon closer examination, the only things distinguishable from the real thing are the stock, the rear sight, and, of course, the valve handle sticking out the side.

Again, that is AMAZING!

[jackssmirkingrevenge]

Very nice build, it's not often that fabricators here pay so much attention to aesthetics - myself included, as I often insist "pretty is as pretty does" - but when they do, the results are usually impressive.

Let's see it in action though, damage shots/videos

[john bunsenburner]

Pretty damn amazing, you make most of us look pretty bad...Anyway, great job on the replica part, i hope you make a few more guns(i am trying my self at the M1A1 Thompson).

Out of personal intrest what tools do you use for making this?

How is the performance of this babe, do you have a firing video?

[chinnerz]

wow that looks really nice!
puts my guns to shame

[FighterAce]

Thanks guys!
I got some footage but I still gotta edit it. Hopefully it will be done till next week.
I never thought of a destruction video thanks for the Idea, I'll do that as soon as I get some free time.

EDIT

Out of personal intrest what tools do you use for making this?

Rough cutting is made by a hand modeling saw and pretty much everything else using scalpels and my dremel 300 tool.

[FighterAce]

Heres a quick demonstration of what these nail darts can do...
I shot this fanta bottle at a distance of about 3 meters.


As you can see, the paper cone got stuck inside but the nail made a clear pass through.

These shots were taken while I was recording the rifle in action...




Here I got a relatively tight group at 6 meters.
All 3 nail darts penetrated the 2.5 cm thick wooden target (dimensions of the target are 1 by 1 meter). One of them cheated cause it went through the connection point of 2 boards so you cant really take the middle one as max penetration

[jackssmirkingrevenge]

I've been looking at your other projects, very well made in terms of aesthetics so you clearly need no lessons there. In terms of performance however, while you've perfected the sprung ball valve mechanism, you can get a lot more efficiency from other valves like QEVs, and since you're working with small calibres, you might want to look into higher pressures and smaller chambers, maybe even get a multi-shot capability.

I see a lot of potential for even better projects, keep up the good work

[FighterAce]

I've been looking at your other projects, very well made in terms of aesthetics so you clearly need no lessons there. In terms of performance however, while you've perfected the sprung ball valve mechanism, you can get a lot more efficiency from other valves like QEVs, and since you're working with small calibres, you might want to look into higher pressures and smaller chambers, maybe even get a multi-shot capability.

I see a lot of potential for even better projects, keep up the good work

Do you mean homemade QEV or ready made from the store? I've experimented with homemade QEVs but they are very bulky and theres more air comming out the plot valve then the actual QEV.
I figure that my guns could look almost 100% real with QEV valve because there would be no handles/springs on the outside but the only way I can do that is to buy a QEV... I'm not sure hows the air flow on them tough...
I forgot to mention that the M4 has a multi shot capability. Between the 2 valves theres a 4cm connector that holds enough air at 150 psi for 2 decent shots. I wish I could go beyond 150psi but then I'd need an air compressor or something and thats way outside my budget.

[POLAND_SPUD]

you can build a fridge compressor... you can find more information on them in my thread here

there's more air coming out the pilot valve then the actual QEV

so your valves must have had some flaws in their construction

you can find more info on piston valves here

But IMO you'd be better off with a QEV (Quick Exhaust Valve - a commercially available piston valve used in pneumatics, it offers better performance than most home-made piston valves)

[jackssmirkingrevenge]

there's more air coming out the pilot valve then the actual QEV

so your valves must have had some flaws in their construction

Agreed