That would depend on the exact bullet and loading. Some soft points are fast opening with thin jackets, others are slower opening with thicker jackets. Some have better BC's than others. Most soft lead tipped bullets are ballistic garbage so even in magnums, much beyond 600m is really pushing it as a matter of generality.
For my money, as long as it's still supersonic it's fine but I don't push my hunting distances past my personal chip shot distance. Beyond 300m is starting to get into my "get closer" territory despite being extremely comfortable shooting in competition settings to whatever distance my bullets will get to and still be supersonic.
This is what I was asking for. Thank you. I figured 700 yards would be about the max.