Was looking at this myself recently as I was getting worried about my vinyl collection. For me 100 records was about 22KG. These were dance records mainly singles. I was placing a shelf worth (100) on scales and averaging them out.

My bedroom has about 2000 records on shelves 5 high. Joists are 2x8 on 16" spacing. Length of joist 12ft. Records are across a load bearing wall. They spread across 7 joists roughly. House was built in 1970.

I don't think you need to worry but I think your records may weigh a bit more than what you estimate. I recon 300-350Kg

I am currently selling some of mine I don't listen to, to lighten the load so to speak