I'm no expert, barely a rookie. But I have taken one deer w the load you describe.

I shot a 2-3 year old buck with a 255 Keith moving around 1000 fps. I didn't get the blood trail I wanted (no blood could be found). I'm not blaming the bullet or the load, my shot was a little right of where I wanted to hit. If I stick with cast, I would use a WFN or LFN next time. I have been having good luck accuracy wise with the XTP's and might just go that route for my next deer season.

story here. I guess I never posted it here?

Correction to story, it was a hard cast 255 from doubletap, not Buffalo bore soft cast. I happened to look at the brass later that year from the hunt. At that speed with a SWC design, I think you benefit a lot from "softer" cast bullets.