You own the 8mm Mag and I don't, but bear with me here. Your cartridge is capable of putting out some real horsepower, and 3000 fps at 175 grains ain't near what it will do. Heck, my .300 WSM will do that with under 70 grains of powder.
If I wanted to shoot an elk in the next county with a cartridge like yours I would be using at least a 220 grain bonded type bullet at around 2800+ FPS, sighted at 2-3 inches high at 100 yards, and limit my shots to 300 yards max.
I personally CRINGE at the thought of a 300 yard shot under hunting conditions, and I shoot hundreds of rounds a year. A gut-shot towel head in the Iraq war might be acceptable, but a gut shot elk in the USA is NOT!
Of course, you may be a much better shot than I, but then you wouldn't have asked, either. Not trying to be a smart-a**, but It would be a shame if you spent your entire hunt looking for a sick animal. Four hundred yard shots at game are for writing stories about, not doing.