Meprolight M21

[renegadecow]

I've always been attracted to reflex sights both aesthetically and functionally. They're relatively low profile, sleek, light weight, and the sight picture isn't impaired greatly by its housing compared to something bulky like an Aimpoint (or a red dot ACOG, those are just horrible). The problem of course is that no airsoft-grade replica exists and while the price of the real one isn't completely unattainable, its still just too much for me.

So here's the deal; I want to MAKE a Meprolight M21 replica which is this guy:

 

And I plan on doing so by using this red dot sight:

 

I know what plenty of you are saying, "that RDS is a piece of poo", "its hard to make lens protectors for it", "its a plastic piece of junk". While I must agree to most of these points, there still remains the fact that I'm stuck with the donor RDS and its not all that bad considering it actually holds zero when mounted on my Socom Gear GBB N4 (same as WE M4) which means plenty for $30 optics.

 

Now here's what I'm planning. I build a clip-on housing covering the entire RDS which looks almost exactly like the M21. I've already checked the measurements and everything surprisingly fits inside. The only discrepancy is that the real M21 has a 30mm lens while the cheapo RDS is fitted with a 24mm objective. It will still function exactly like original RDS with 11 brightness settings and a red dot (apparently the M21 has a red dot too) but you have to turn it on/off with the housing removed and just reinstall it afterward. Now, the big advantage in having the housing is that I can easily mount polycarbonate protective lenses on it covering both sides of the reflective lens. I can only make the housing out of PVC right now but I've recently come across a small company that can have most anything that you present to them cast in polyurethane (loads tougher than pvc but still plastic).

 

At first I was considering on making the whole thing from scratch with only the actual lens being cannibalized but I'm not familiar with actual fiber optic rods. I found some cheap acrylic fiber optic rods online for like $2.50 per 40" of the stuff but I have no clue if the material can accumulate enough light to project the dot or if I could even bend it so as to loop it around in a one piece spiral like on the real thing. Plus there's having to source out some tritium or similar so I could use them in complete darkness. I was thinking of using a bunch of Nitesiters thinking that the glow of the stuff would be enough to power the fiber optic at night. But again, this is untested and I'd rather have some input from you guys with regards to this stuff first. For now, I'm just set on making the housing.

 

Then when I'm done, I plan on mounting it on my N4 like the IDF do:

[Samm]

I think it's a great idea!

 

got these if it helps;

[renegadecow]

Goodness that was fast! And a big help too. If I ain't asking too much, would you happen to have a shot from the rear? I haven't found any showcasing the inside of the hood or at least what the inside of the channel on top looks like.

[Samm]

Sorry to say they're not mine, just random photos I happened to have off the net. Using my massiv innit skillz I managed to find this guy, he would seem to own one and also like taking pictures (being on flickr and all ):

http://www.flickr.com/photos/15498418@N02/3234426782/

 

 

[renegadecow]

Thanks again, and I also stumbled upon this:

http://tigerland-blog.blogspot.com/2008/06...ht-mepro21.html

[Samm]

Ahh you beat my google proficiência!

 

Looking at those, do you think it would be possible to leave the brightness adjust open to access for a screwdriver through the top there?

[renegadecow]

I was thinking just that though the battery cover (the part with the slot) should be fairly tight to begin with so it wouldn't just come undone when you try to turn it.

[renegadecow]

I've finally started on actual work for the Mepro this morning and I got carried away dremelling up until 10pm in the evening. I've finished constructing the body and the front bit which holds the fiber optic material on the real thing. On mine, I made it function as a lock: Slip body on RD, put on front part then screw on sides. Beats my original concept of just making everything snap-on. I've also encountered some major problems with dimensions. Since I had to work around the RD, I made the necessary adjustments, which makes this a less than exact replica. I am however gearing up for MkII even though I haven't finished this one yet. For that project, I'll be chopping up a 30mm red dot (tasco or aimpoint) for the lens and will try to incorporate a true fiber optic system plus I'll try to make things as exact in scale to the real thing. But thats for later, for now I have these:

[Mat]

Very nice

[masakarijoe]

dude... would you be willing to make one of these, and sell it maybe? or possibly when you make a new one, you could sell me the old one here...

i would be interested if so.

pm me if we might be able to work something out

it looks great

-Joe

[Yuri]

You are like a human CNC machine.

[T0p Sp!N]

You are like a human CNC machine.

 

Indeed.

 

A PVC forming master.

GJ tol.

 

:thumbs-up:

[chas]

Dude... that is... awesome!! I must admit that when I first saw this thread I didnt expect much from the eventual result. you have only finished the first phase and it is already stunning.

If you find a way to imitate the lime green front lens, Id like to hop on the "please make one for me" band wagon.

If you could make a mold for PVC casts of these, you could start a businness!

 

Effin' A +++, man!

[renegadecow]

Thanks guys. If enough people become interested I could have these molded and cast out of polyurethane, a bit tougher than pvc and will have uniform color in case of scratches. But I will be needing quite a few show of hands as the cost of the initial mold is a bit pricey. Otherwise, I suppose I could squeeze in the few odd hours of dremelling madness to make them in the same manner as the first.

 

Chas: Gonna be a problem with the lime green tint. I admit thats one of the things that drew me to the Mepro but interfering with the lens coating may affect its function unless I know exactly what coating it is. When I gear up for MkII, for multiple copies I might have the lenses made instead of cannibalizing unwanted red dots. Maybe this way I can have them coated with the green stuff.

[masakarijoe]

well count me in either way, depending on price.

-Joe

[nada987]

Renegade, how did you get such clean lines on that prototype with just a dremel? I see it, but my brain doesn't want to believe it. Nice work!

[renegadecow]

Which lines specifically? I find that my dremelling technique adjusts depending on angle of attack. And on some parts I don't use a rotary tool at all (files, sanding blocks etc.)

 

Also, I need a bit of help here. Has anyone seen or held an M21 up close? Theres one at a local gun store but their lights are dim and they wouldn't let it out of the glass case. My problem is that the white part for the fiber optic housing vary in color from white to gray in different pictures. I've gone ahead and sprayed mine flat white but it looks kinda naff. I'm wishing I bought "dolphin gray", a very light gray but I'm not even sure if the real thing even is gray.

 

Camera flash made the white glow, but thats really flat white. Will remodel the front part later for the transparent cover below the lens. I'll be using a semi-opaque "smoke" plastic folder.

 

I've also put in more detail mainly the fake adjusting nubs.

[kelo 1 1]

+1

 

Its things like this that make me want to build things.

 

Kris

 

 

[Samm]

That's ridiculously amazing, well done! You must have some higher resolution photos than that!

[renegadecow]

Marginally better photos. The camera is still made of poo. Note that there's some discoloration going on when I tried to retouch some parts (couldn't wait for paint to dry) with acetone. Will do a once over when everythings completely done.

[nada987]

Which lines specifically? I find that my dremelling technique adjusts depending on angle of attack. And on some parts I don't use a rotary tool at all (files, sanding blocks etc.)

 

Well... How about hollowing out the shell in the back where you look through it to see the lens? The semi-circular hood portion seems flawless.

 

[masakarijoe]

you must sell me that.

looks awesome! when this is finished, im sure it will look even better.

do you plan on adding QD throw levers?

-Joe

[renegadecow]

Nada987:

Firstly, I didn't work on this with a solid chunk of pvc in case thats what you're thinking. I break down a design to its simplest polygonal shapes and proceed from there; kind of like building Lego's only you have to make the parts as well. In the case of the hood (has a two step thing going on apart from the front most part that has the slits for the fiber optic) its made of 6 pieces of separately shaped parts then glued together and sanded down to remove the seams. The top part is half a section of pvc pipe cut with a hacksaw; one I left in its unaltered 32mm diameter while the step-up part I had to increase a bit by reforming it with heat. The sides are from flattened pieces of pvc.

 

And at this point I haven't even mentioned using a dremel yet. Actual heavy dremel use comes in the slits on the front part, making the hole for the lens at the front, sanding the sides at an angle (where the side adjustment knob is), beveling corners and finishing up seams everywhere in all of its 20 separate pieces.

 

 

masakarijoe:

Can't source throw levers unless I cannibalize some from a china QD mount. And my rotary tool is acting up so it might be a while before I can start making you a copy, at least until I have it serviced.

[nada987]

Ah... that makes much more sense. I had a hunch, but it was the identical blue color of each piece that threw me off. I did indeed think you had just taken a block of pvc and went to town. Not that this changes the fact that it's quite a piece of craftsmanship. Well done.

[BigAl]

Very well done, you really should look into making a few of these. Put me on the list if you do.