Happy New Year, Clodo.
I would never suggest it is interchangeable. Didn't say that. I worked up to 00.0gr. BLC2 with the 270Speer for 2,675fps(spooky), then found out in a much smaller case, the 9.3x57, that the 270 Speer bullet was not suitable even for a calf moose, although the moose died, the bullet failed to penetrate the rib cage after going through a leg bone. It might have been going 1,800fps at impact. Still have a bunch of those bullets and only use them for fireforming. The muzzle vel. was 2,300fps even.
The might be OK on deer, but read where a fellow shot a whitetail vertically from a tree stand. The bullet hit the spine and came apart right there, not penetrating the lungs.
That was his report. His rifle was a 9.3x62 & IIRC, his load was about 2,500fps.