Here in Ontario Canada 300.00 dollars for a 303 B with a very good bore and wood would be a steel .
The 303 Mark 5 was known to have a wondering Zero ,some say because they used a lighter reciever than what was on the Mark 4 .
Some Mark 4's were cut down and restocked to look like the Jungle carbine which then could be sold for the higher priced Mark 5 .So I guess if you found one of these Fake mark 5's you have a good shooter .
Victor If you were in Canada I would gladly buy your Mark 5 carbine . Looks like a very nice unit .