I have 3x9 scope on a 30/30. My farest shot is about 100 yards at the most. What is a good range for the different power varitions on the scope? In other words if I have my scope set at #5 what is a good distance in yards to shoot?

Your thread title suggests you want to sight in a scope. Your actual post didn't ask that. Generally I suggest setting the scope on the lowest power setting, in your case 3x and leave it there until you actually need to take a shot long enough that you have the time and need to adjust higher. This way you have the widest field of view and less noticable instability in your hold. You may never need to adjust much higher and if your shots come quickly you may never want to. Here in the west where our shots can be very long and its possible to catch an animal off guard and unaware...we have the time to adjust up and steady from a rest. Other places may not.

I would site the scope in at 25 yards at the 3 power setting, then move to 50 and make any necessary adjustments and then move to 100 and after you have it set, recheck it on the highest power setting. Then you should be good to go. A lot of the older cheaper scopes tend to drift the point of impact when you change power settings. So it is best to just put it on the 3 or 4 power setting and leave it there.

A 30/30 in my mind is a 150 yard gun. For some folks that are really good shots, perhaps 200.

Countless deer have been shot within these ranges with a straight 4 power scope.

The power you set your scope on does not correlate to the range you can shoot. With my shotgun, I set my scope on 2 power (1.5-4.5x variable scope). The majority of my shots will be under 50 yards. If i see a deer at 100, I usually have plenty of time to turn the scope to 4.5.

The power setting on the scope won't effect how far you can shoot. Shoot as far as you feel comfortable with that magnification. I leave my power setting set at 4 and crank it up to 12 if I need a long shot (which is usually).

You don't need no stinking scope on a 30-30! But seriously, I would set it at 3 or 4X and that will be good enough for shots to 200 yds.

i can zoom my scope all the way in on 100 yards and blow out the bulls eye all day long..gl

Generally "bulls eyes" don't run when spooked and you will actually have all day in which to shoot one. Deer....not so much. The field of view on 3x is just about exactly three times wider than at 9x. Even here out on the open prairie where sometimes its not possible to get any closer than 250 yds. or so we don't always "need" to zoom into max power. It can be handy and if time and circumstances allow we do.

...................Yup......