I have similar "loose forearm screw" problems with older SxS's.

One solution, if the wood is old and worn, is to inset 1/3 of a toothpick into the hole, before re-inserting the screw. In some cases, you may want to add a bit of wood glue to the toothpick, and then let that dry overnight, before re-inserting the metal screw.

gold40