This is a repeat from an old post of mine. If you feel the need to beef up the wrist, I think this is easier and just as effective as steel rods or wood dowels:
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A rifle I was building had a grain direction through the wrist that looked like a potential problem. Every time I looked at the unfinished rifle as I passed by the bench, the grain run out started to bother me. So rather than wait until the wrist broke one day and then try to fix it, I thought I would be pro-active and fix it before it broke.
I routed out a deep groove 3/8 inch wide and 1.25 inches tall through the entire wrist area excavating the existing inletting for the trigger, trigger plate, and rear of the trigger guard.
I then cut a straight grain splint out of a scrap of the same stock blank and cut some narrow grooves in it to allow me to squeeze the epoxy out around the splint and get it fully seated in its groove. (I have also used a hickory splint with great success).
One last full check fit before the epoxy was mixed.
Splint epoxied in place....
After a day of curing, the trigger, trigger plate and rear of the trigger guard were re-inletted back where they came from.
If the stock breaks at the wrist after this, I'll make a new stock.