I found a Model 39A "Golden" rifle today for a decent price and in otherwise great shape but with a loose lever.

Lever drops about 3/8' in all action conditions: breech closed/hammer down, breech closed/half and full-cock, breech open. Slightly looser with the breech open,

What causes this, and can it be fixed by adjustment or does it indicate missing, worn-out, or broken parts? Can it be fixed by Bubba-level gunsmithing (mine)? I'd really like to buy this but don't want to get into a long-term, expensive hassle with it. Don't mind minor owner repairs that will allow me to beat the price down a bit....

Any wisdom/experience gratefully received!

My 39 TDS had the same experience. It was an $80 gunsmith fix (min. charge, less than one hour). I think he said it was a weakened or broken spring. It's been good since.

Thanks! A small fee like that I can stand, if it gets this rifle back in service! Anybody got a gunsmith that is "woke" to 39s? My usual fallback for vintage rimfires is Ahlman's but they are in MN and the shipping from CA is pretty brutal now....CA or AZ or OR or NV would be better for me.

It's a broken or missing lever spring, they are held by a single screw through the bottom of the receiver in front of the lever pivot - if the screw is still there it's probably just broken.
https://www.gunpartscorp.com/products/1568780C
https://www.gunpartscorp.com/products/1594660C

I changed one in a Model 1897, It's been a long time since I did this but I think I found it impossible to get the spring flexed enough to start the screw with the lever in place so I removed the lever, started the screw leaving it loose, and then was able to get the lever back in.

Here's a picture showing the spring in an earlier solid frame gun where it's easier to see and in a later takedown.

sometime its just that screw is loose. mine had a drooped lever too (not as much as yours) and i tightened that screw up and solved the issue. either way i wouldnt let it stop me from buying it.