A second major group of British bun ingots date to the Roman period and are found mostly in the copper-rich highland areas of Wales and in Scotland. They are heavier than the LBA examples, with weights ranging between 12 and 22 kg.
Some have stamps clearly dating them to the Roman period including an example that reads SOCIO ROMAE NATSOL. The term "socio" suggests that the ingots were cast by a private company rather than by the state. Fraser Hunter reassessed the context of the Scottish examples and some of the unstamped Welsh examples and argues that they could in fact date to the Iron Age or at least reflect native rather than Roman copper working. Although ingots of any sort are not common in the British Iron Age, planoconvex or bun-shaped ingots exist, e.g. a tin ingot discovered within the Iron Age hillfort at Chun Castle, Cornwall.