Skye crofter, Jonathan MacLeod (d.1874) was shot in the leg at Waterloo and lived with the bullet in his calf for ~60 years. When his son Angus was interred with him at Kilmartin, his grandchildren found the bullet in the earth, 72 years after it had been shot.
References
Dundee Evening Telegraph. 24th March 1887. pg. 2
1887 MACLEOD, ANGUS (Statutory registers Deaths 112/2 7)