JB over the 8 will be the date it was reproofed . JB is the date code the 8 is the inspector .This will be 1983 .Will stand correcting on this but 4Tons will be the old Standard proof for loads such as Alpha max or Hymax . Magnum would be 4&2/2 Tons .
In 12 bore 4 tons would be Standard 3" or 2&3/4 magnum equivalent .

Last edited by gunman; 02/19/24 07:59 AM.