Once long ago in a Highland town far away there was a kindly police sergeant. On the day he retired he decided to pass on his favourite truncheon to his prodigy. The main reason it was his favourite truncheon was because it was far heavier than regulation. And a heavier truncheon breaks skulls and arms more efficiently than a standard weight one. This extra heft was created by drilling out the core of the truncheon and filling it with molten lead. Maybe lead from the local newspaper's Linotype machines. I suppose the trick was knowing how much of the truncheon core to gouge out. A good police officer wouldn't want their lead bar disguised as a truncheon to splinter apart when applied to a bad guy's upper arm.