Materials:
-phillips head screwdriver
-awl
-hammer (not required, but will make it a little easier)
-epoxy putty
-1/2" brass tubing, about 1 1/2' of length
-file/sandpaper
I already had everything except the brass, so total cost to me was about $4.00
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Firstly, take out all the screws to open 'er up. Then you're going to have to punch out the two pins on the connecting part of the stock. This is where you need the awl.

Instead of replacing the supports with the brass, I measured all the points and cut it to fit over the existing supports. So this nub needs to be sanded so our brass can slide over. Just a little bit.

Once you've measured and cut your brass, mix your epoxy putty, and use just enough to coat the plastic supports so that the brass slides over snugly. But excess can obviously just be wiped off. Unfortunately, I was by myself here and didn't take pictures because I was wearing gloves to work with the epoxy. But the other important step here was to pack the joints with the putty, so that there's no flex where the brass meets plastic in the middle and at both ends.
So here it is sanded and ready for paint

And... with the first coat of paint.

Total time (not including time for epoxy to cure 24 hrs) this only took me about 2 hrs. I wasn't super picky about sanding at the end before painting, so it's not super clean, but if you wanted to, it wouldn't take much longer. The stock has a much nicer weight though, and no flex whatsoever.