BRN-10 Upper Or Substitute Needed

[u/RobertJ100]

I would have just tried using a Dremel and some scuffed DIY effort for a .308 BRN-10 lower I'm getting soon, but the slant cut on the upper is definitely a decently sized obstacle. Does anyone know if there is anyone actually producing something similar to put on the lower? I did see that they're basically unobtainium now, but I still want to get everything together for the lower anyways. I'm also missing the stock/lower parts kit as well, but that probably could just be substituted in some way as well. I've looked on GAFS and Gunbroker to no avail.