THE Arms Collectors Guild of Tasmania has slammed the theft of historical firearms from the QVMAG Museum as "appalling".
President John Green said the gun belonging to 19thcentury bushranger Martin Cash had particular historical value for Tasmania.
"It was used by him in some of the crimes he committed," Mr Green said.
"Being a bushranger, it would have been originally stolen by him.
"And other criminals have now perpetuated the whole thing.
"We have been involved with the museum over many years, with their arms collection.
"We definitely hope for their return."
Mr Green said the firearms would be sought-after collectibles, but he speculated they would more likely be used to commit further crimes.
Cash, a career bushranger, was born in Ireland in 1808.
Convicted of housebreaking in March 1827 - he claimed to have shot a love rival in the buttocks - he was transported for seven years to Sydney.
He sailed for Van Diemens Land in 1837 and continued his criminal ways, ending up in Port Arthur.
Cash was one of the few to escape the convict settlement, by swimming past Eaglehawk Neck.
He was known as a "gentleman bushranger" for his ability to commit crime without unnecessary violence.
An ivory walking cane gun was among his possessions.
Cash later shot a policeman in Hobart and was transported to Norfolk Island for murder - supposedly "for life".
But after a decade there he returned to Van Diemens Land.
He settled at Glenorchy and during his later years he was known as a cheerful, popular scoundrel.
Cash died in 1877, apparently from a broken heart, and became known as the only bushranger to have died in his own bed.