Need a detailed description of all markings and features.
The BSA Mercury was made between 1972-1980
BSA cadets were made between 1946-1959
BSA actually stands for "Birmingham (UK) Small Arms" they first made guns; hence the 3 crossed rifles on the badge. Yamaha, who first made pianoes, copied the idea putting 3 crossed tuning forks on their badge.
BSA made several different air rifles. Unfortunately you did not state the model number and that is critical. You could try to contact BSA and ask them. see the link below.
Probably about 2007 - Gold SR.
I think that 5,000,000,000 motorcycles have been made. The question is how many of the flagship high horsepower 1968 BSA spitfires were made. A few thousand for that year my estimate. Maybe less.
Birmingham Small Arms Co made motorcycles
25
About 4000
It was made between 1948 - 1959. That's all the information I have. You could try the link below for BSA.
This model BSA (UK) was made between 1948 -1959. It came in both .177 or .22 cal
What condition is it in. That determines the value.