Is the San Jose Gun Exchange still open? They lost their FFL many years ago, but the owner kept it open as purely a sporting goods store; I think I was last there about two years ago (right after Covid), and it was open, and the owner was still there. It's on Almaden Expressway, a little north of 85. Coincidentally, the owner is also named Mike. He is an expert on old military rifles of all kinds, and can probably help with good advice, even if he can't sell guns or perform gunsmithing services legally. He's helped me with minor problems on my M1 carbines (without even seeing them, just from me describing when they weren't cycling).
Personal tip: Mike is very hard of hearing. He can seem gruff and rude, but that's to a large extent simply because he doesn't hear. So try to be there when the shop is empty (not much background noise), speak loudly and slowly while facing him, and he turns into a really charming old guy.