Anchor chain for my Nilsson Windless

[CHEERIO]

I have looked for, but haven't located 5/16 chain to fit the gypsy.

[s/v Jedi]

If you're sure it's 5/16 (so not metric 8mm) then you probably have ISO short links. You might have been looking at BBB or proof coil standard chain.

You can buy different chain wheels for your windlass to fit different chain. Bit I'm pretty convinced a product like ACCO 5/16" G.43 ISO chain will fit.

ciao!
Nick.