I have been a competetive shooter for over 40 years, using micrometer receiver sights to shoot scores not significantly different from those shot with a powerful scope, so I know what iron sights are capable of. I have been a hunter even longer than that, and almost without exception, my hunting rifles, even the heaviest, are scoped. In fact, the only hunting rifle I own and have used extensively without a scope is my .505, and, were I to take another trip to Africa, I am not sure I wouldn't fit it with a scope.

The advantages of a scope are numerous:
1. Positive identification of your target. This is particularly important under less than ideal light conditions and in heavy brush.

2. Single aiming point: no need to concentrate on alignment of front and rear sights, just aim and shoot. (Even with a receiver sight, a certain degree of sight alignment is needed).

3. Positive aiming: With a scope there is no need to aim "for center of mass." The shooter can pick out the exact spot he needs to hit and concentrate on it at ranges far beyond what he would be able to do with iron sights. A typical fron sight may largely obscure a target at 100 yards, let alone 200, and the difficulties in "holding over" at longer range are multiplied by the fact that the target is obscured.

4. Observation: The shooter can observe his target at the same time he is aiming. No need to switch back and forth between sights and binoculars to make last second observations. There is a big difference in shooting an animal which is oblivious to danger and one which is poised for flight. Knowing that one has all the time in the world to squeeze off a shot or that a once-in-a-lifetime opportunity is about to decamp is a great advantage the scoped rifle gives a shooter which the iron sighted rifle denies him.

The disadvantages of a scope are:

1. Fragility. A scope is more likely to be damaged than (particularly open) iron sights. I have never found this to be a problem, but equipping your rifle with sensible iron sights as a back up makes sense even with rifles of low recoil. It's like taking that umbrella with you, knowing that it probably won't rain because you have it.

2. Field of view. Higher powered scopes not only have a restricted field of view, but may have an exit pupil small enough to cause difficulties in lining up with it. The low powered (1-4X, 1.5-5X)
scope solves both those problems.

3. Difficulty in "catching aim". This is generally a factor of using to powerful a scope with an objective lens which raises the height of the scope mount above the line of aim the rifle was stocked for. A straight tube scope can be mounted as low as iron sights, particularly if a side mount like the Griffin & Howe is used. Amost all of my heavy bolt guns have G&H mounts with Lyman 48 receiver sights as a back up.

4. Heavy recoil can cause an unfortunate collision between ocular and forehead. This problem can be avoided by using a scope with sufficient eye relief. Unfortunately, modern scopes are not up to the standards of the pre-war Noske and post-war Lyman Alaskan scopes, whose eye relief was long enough to allow them to be positioned far enough forward to permit the use of an unaltered Springfield or Mauser bolt handle, but 4" should be enough to prevent such an accident from occurring. My .450 Watts has a Lyman Alaskan in a G&H mount and my .577 a Noske in Weaver mounts. The .500 NE I am having built will feature a Leupold 1.5-5X VariXIII. I have no half moon scar above my aiming eye.