well that sucks, I hate when things break and end being hard to find replacements !
would this work??(didn't mention if carbine or full size)
https://www.gunpartscorp.com/products/449620
or
https://www.gunpartscorp.com/products/1786530
OR maybe
adding some pictures to get us to try and make some suggestions
but if it crack at the barrel screw my guess is, the screw was loose allowing recoil to put pressure on the screw as the barrel moved in the stock
there are some pretty incredible epoxy's on the market today that Might help repair this stock pending damage
or maybe can mill out a section and fill in with a combo of epoxy and or metal pin's plates or?/
that or talk to some good stock makers and ask if they can make you one using the broken forearm as a template for them, I imagine they can, just if costs are worth it to you??