...I know and have seen several top name gunsmiths using the same tool -- a piece of oak or hickory.
And ever last Man Jack among them said "don't do this at home" while they did it!!
Proofing in Italy is a "blue pill" load of 30% over the max. http://www.bpcr.net/site_docs-results_schedules/documents/pedersoli_proof_rules_and_allowable_limits_09-04.htm