You are very lucky in that BSA guns were machine made which enables spare parts to interchange and be fitted easily. If anyone can help it is John Knibbs in England. You can contact him here http://www.s248611434.websitehome.co.uk/links.php BSA is mainly concerned now with air rifles but I know he has a wealth of knowledge about all BSA shotguns and rifles and a wealth of spare parts too. He will no doubt be at the Midland Game Fair this coming weekend so may not be able to reply straight away to e-mail. Good luck. Lagopus.....