Sounds like Dick Austin is being an idiot again.
I think you are likely right at the edge with that load. 3200 or so FPS is what I'd be looking for with that powder.
Steelhead I welcome you to stuff 51 gr. into a 257ai; I hear blue dot will go 3200. Try it.
To OP, steelhead's an idiot. Don't load anything he says until you've double checked it someplace valid, like a Hornady or Nosler reloading book. In fact IMR/Hogdon has their info online which is where you should check. Repeat, steelhead - big mouthed idiot - IMR info good.
