The link below puts you directly into one of the very best Buck Mark sites. The guru is "Chim".
Ask your question (it's not an unknown problem). You will get good answers.
And most likely you will be directed to Chim's photo's on dissassembly.
Be careful taking off grips. Most do it inside a plastic bag. Springs fly.
And, the sticky "Buck Mark Starter Thread" at top contains a huge amount of Buck Mark info.
Browning - RimfireCentral.com Forums
Congratulations on having a Buck Mark. We belong to an exclusive cult, you know.
Good Luck !