Genreally speaking the heavier bullets per caliber are made for big game and the lighter ones for varmints or real thin skinned game. The 120 grain 7MM would be a Varmint bullet where the 140 and up are intended for big game. The 150 grain 30 caliber would be fine in the 308, 300 Savage speed range where the 180 in the 30 caliber would be a better choice in the 300 Mags. Of course range and remaing velocity would play a factor. The 165 Grain 30 caliber might be about perfect for deer hunting in all the 30 calibers.