not happening. 500 ft lbs, yes, 600, no.
It's not that difficult to get 600 ft lbs out of a 4 inch M-28. As I said I use 150 grns @1328 FPS. That's not a hot load but its 588 ft lbs. If I was to use 158s at the same velocity (doable) it would be 619 ft lbs.