I have had this stock for a while now, I have never seen other one like it. At first I thought it might be from the Colt ACR rifle but have only found the one picture of the rifle.

It looks like the colt acr stock to me, I am going by the picture on the wiki page. I may have to keep an eye out for one of those.

Looks similar to me but look at the reinforcing rib on the bottom of yours versus the one in my photo and notice that your's does not come out as close to the end of the stock like the known one. Here is a pic I took of the real deal. Sorry, not the best photo but I know it's real at least.

Also, notice the difference in the latch "box" and the screws? or what ever that hardware is in yours.

Perhaps there was more than one version of it? I'm pretty sure there is a photo of it in RBR2 but I am at work and can't check my copy at the moment.


Here is one that looks like yours


and photo is from this thread

I like it

Reminds me of the modern day B5 Systems Sopmod Stock

That stock screams Prototype.  Maybe a prototype ACR or B5, SOPMOD, etc.  It looks very much like a Colt product.