Does anyone know what aftermarket sights are available for the 509?  Preferably fiber optic and tritium front sights and plain black rear.

It takes standard Sig (and XD?) sights, I'm about to put a set of Sig X-Rays on mine.

Thanks

It looks like the x-rays are 8/8 size sights. Is that what the 509 needs?

I measured the 509 sights with calipers. The rear is .235 and the front is .250. Those don't seem to match against the sig chart.

FN customer service says the FN 509 sights are modeled after 8/8 height Sig sights. I'd see how yours prints first, then go from there. You'll find quite a few combinations of heights for the Sig X-Rays (I see varying combinations of 8's and 6's, Sig CS could probably even hook one up with 7's).

Mine needed no adjustment and the stock 8/8 gives a perfect '#2' sight picture (top of front sight bisecting poi), though as always there may be minute variations that would make it prudent to see where your specific one prints.