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I would try a repair first to make a usable rifle, but it would not hurt to see if you could fine a replacement forestock. That is a kind of nice piece of wood.
One thing I do with cracked stocks (if you can), is to use a heavier staple that is used for construction. These come in various widths. If you have an area that does not show, you can take one staple, and drill two slightly smaller holes in the end of the forestock. Make these holes the width of the length between the points of the staple, Then, using a Dremel with a thin blade or a thin wood chisel, cut out a channel that connects these holes. The channel does not have to be deep, but it should be deep enough so that the staple is recessed when you drive it in.
Apply some epoxy glue to the crack, the two holes you drilled, and some in the channel you cut, then drive the staple in. Try to clamp the cracked pieces together if you can, and the staple can also be put in after you have glued the cracked pieces together. Coat the channel with a bit of epoxy glue, and the staple will act as a tie or reinforcement, and be out of sight .
Heavy rubber bands work for holding the pieces together, but I prefer surgical rubber tubing. You can use different lengths and tie it easily.
In this case, I would think about using two staples, one for the side and one at the bottom, possibly angled a bit on the bottom one.