So I am picking up a Winchester 1897 takedown from 1922 with a bad main/hammer spring tomorrow. I technically have all the parts for a Norinco clone I could swap into the shotgun, but I'd prefer to keep it as original as possible. The spring looks pretty easy to source, but I'm going off the current owner as I have yet to lay eyes on it. How difficult is replacing that spring? Any tricks or tips to it?

It's not hard to replace, but wouldn't be a bad idea to find repair manual showing disassembly and reassembly. I did a complete teardown/clean/reassemble on a 1918 year make and the manual made a big difference. LOTS of small parts in the action slide/carrier/bolt group.

Got what was left of the old one out pretty easily. Looks like it should be pretty simple to replace now that I've done that. Looking forward to shooting it eventually, it was well cared for and it's very smooth