Re: 17-4 annealed and double heat treat stainless.
I suspect indefinite if shot at 100 yards or more. 20 yards vs a 140 grain out of a 270 wsm. I would have bet on the 270. I also hit it with the 77 grain 223. Found the ass of the bullet glued to the plate. No damage. We will see. I get the trim cuts off our saws. Up to 22 inch steel, every flavor. And up to 12" on the stainless. 303, 304, 316 and 17-4.