Brit Plumber has it correctly. It is to give a new lease of life to worn out Mk2 guns where it was impossible to tighten the barrels. Only needy guns had them and they would come loose in service on the Mk2/1 guns
Brit Plumber has it correctly. It is to give a new lease of life to worn out Mk2 guns where it was impossible to tighten the barrels. Only needy guns had them and they would come loose in service on the Mk2/1 guns