Few hunters can shoot up to their rifles on demand, under field conditions. Most big game presents a large target at close range, so there is no advantage to the big game rifle that shoots quarter minute groups under normal big game hunting conditions. If you are tempted to take a target rifle into the field, consider some of the disadvantages. A target rifle might not be any more accurate, or even as accurate as a good hunting rifle when both a loaded with bullets suitable for killing big game.
Consider the situation where the rifleman has ordered a custom barrel with a rate of twist optimized for 155 gr bullets, then loads up a 200 gr bullet to hunt moose or big bears with. Chances are that rifle will no longer produce the quarter minute accuracy he is so proud of, it may in fact not even properly stabilize a long 200 gr bullet. The first shot is the important shot. It must go exactly where you want it to go from a cold barrel, in other words the rifle must be sighted in for the cold bore shot. There are no alibi shots or sighting shots in the field under normal big game hunting conditions. If the follow up shot impacts 4" away from the first shot, it doesn't make any difference because by that time the animal could be in flight and shooting tighter than 4" would be a fluke under those circumstances. If your ammo is loaded to produce the ultimate in accuracy and you seat your bullets hard into the rifling with fairly light neck tension, unloading the round could result in the bullet being left in the throat of the chamber. Bullets seated long enough to contact the rifling results in ammo that is often too long to feed from the magazine, and single loading a bolt gun in the field should be considered a disadvantage.
Then there is the weight of the rifle, which in the case of my target rifle is 20 pounds and I have no interest in packing around a 20 pound rifle for 10 hours, but that depends on your hunting style. If you have a wide open vista to watch from a static position, the heavy target rifle would be of little inconvenience, but that is a different game.
The high powered scopes suitable for use on the range are a poor choice for normal big game hunting, due to their delicate mounting, large physical size, and tight field of view.
Many target rifles have very light triggers, and carrying a heavy loaded rifle that requires less than a pound of trigger weight to fire leaves something to be desired.
In recent years, we have seen an increase in the popularity of short, heavy barreled factory .308s like the T-3 Tactical, the M-700 Police, and short barreled versions of Accuracy International's AE and the Styer SSG. These rifles are more portable than their long barreled cousins, and if you want a high quality do it all rifle that sees more use on the range than in the field, they are more practical for normal big game hunting than a full blown target rifle. Still, I would be inclined to use a true big game scope on the day you go into the thick stuff after a moose or whitetail, as even a 4-12X40 has a pretty tight field of view. The hunter who hunts from a snowmobile or quad is not bothered by a little extra weight in his rifle, provided the length is not cumbersome.
The long range big game hunter is the exception to the rule. He must use a very accurate system, and be able to work out his firing solution beginning with a very precise calculation of range. He has mastered the difficulties associated with shooting in wind and mirage at extended ranges. If he is familiar with the area, he may very well have prearranged those places where he is most likely to spot game. His rifle is probably a target rifle/hunting rifle hybrid chambered for a powerful cartridge that has enough residual velocity and bullet mass at a half mile or more to ensure a humane kill on a big game animal. Such a hunter has little in common with the typical big game hunter who almost always shoots within 300 yards, and most often shoots within half or even a quarter of that range.
