I help a gentleman salvage some guns, and parts, after a large wildfire burned his home and numerous others. One of the gun destroyed was a Schuetzen early cartridge rifle. The wood was burned to charcoal, but the metal parts were in pretty good shape. The flames really never reached the guns, but the extreme heat destroyed the stocks. When I started taking the buttplate off of the old target gun I noticed that the acorn on the butt was designed to unscrew. I unscrewed it and got the surprise of my life. The acorn was the access to a chamber in the stock that could be filled with lead shot to add weight, that I suspect was to counterbalance the heavy barrel.
Hungry Horse