Saturday, December 21, 2019

New project time.

So I saw a picture on the internet the other day of what appeared to be a 3D printed AR-15 based bolt action rifle with a traditional rifle stock and I got inspired.  In reading some discussions about it, I became aware of the Ares/Fightlight SCR which is basically an AR platform but with a standard rifle stock and no pistol grip, and I decided I wanted one.  Actual SCR lowers though are $600+ and I'm definitely not going to spend that much.

Good thing I have a 3D printer.  I'll just make my own.  I'm not going to try to make a fully printed rifle, I'll use an off the shelf upper.  The plan so far is to make a printed lower/stock, and use an off the shelf upper receiver and BCG.  This will be a straight pull bolt action rifle, so even though it uses AR parts, I won't need a gas system or buffer tube(the buffer tube is the big one because without it I can shape the stock however I want).  Since the back of the bolt carrier doesn't do much and is in the way on a rifle like this, I'll just cut it off.  I'm going to make it in 7.62x39 because I already have plenty on hand so I'll be using an x39 sized BCG, barrel, and 10 round magazine.

In reading about it, I've learned that 3D printed ARs(and many plastic ones in general) break at the buffer tube tower.  There's a lot of load on that area because of the bolt cycling, but since this will be a bolt action instead of semi-auto I don't need a buffer at all and it just needs to be strong enough to not break if I bonk it into something.

Using a picture for reference, my new lower started as a pretty straight up copy of the SCR lower.  But it wasn't really ideal in my eyes and wasn't suitable for 3D printing.  So I started changing and modifying and tweaking things as I saw fit.  The biggest change I made, other than the whole no pistol grip thing, was to move all the fire control parts up in the receiver .200"  This allows for a shorter reach to the trigger and an overall shorter lower receiver.  You can see here where the new location is compared to the standard AR, the new parts are the darker grey:

Next up was the trigger it's self.  Obviously it has to move backwards a few inches to work with a standard rifle grip.  My temporary solution is to just make an extender sleeve for it.  This is still very much a work in progress and will probably be replaced with something better.  For the time being I'm leaving the original trigger intact, I'll cut it down when I'm satisfied with how it works.  Since this is a bolt action rifle, I don't need the disconnector so the new printed trigger extension slips right over the tail of the original one.  I'll probably eventually make something with some kind of linkage, for now this is just a "see if it works" solution.
Here's where I'm at now.  I relocated all the FCG parts, added reinforcement in some areas because this will be 3D printed, and I got started on drawing the stock.  I got rid of the bolt catch too, it's not really needed anymore and the print will be stronger without it.  The stock is dovetailed onto the lower, and will have a single attaching screw running into it.  I'm not really happy with the stock yet but it's a start.


3 comments:

  1. Will you share the stl with me. I would like to try and make this work for airsoft. Much appreciated

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    1. I have not publicly released my STL files yet, when I do I will be sure to post a link.

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    2. Have you thought anymore about releasing the files ? , now that they have discontinued the scr this is my only hope and this look awesome to me

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