These are ways sold out and a pain to find. Midwestgunworks.com has them in stock. I have no desire to run an aftermarket trigger in my 509's (I actually love the stock), but it doubles as a jig to break it all down if needed.
Anyway, they are in stock
https://www.midwestgunworks.com/page/mgwi/prod/104-130
Anyway, they are in stock
https://www.midwestgunworks.com/page/mgwi/prod/104-130