A 30-30 would be adequate for deer up to 150 yards. The 300WSM would be adequate to 400 yards or better and the 300UM has another 100 yards or more on the WSM provided you can shoot accurately that far under hunting conditions. I wouldn't say that they are too big cause they are 30 cal bullets just like the 30-30 but I would use a "hold together bullet" so they don't come apart under high velocity at close range. If you ever go elk and/ or moose hunting then you would be set with one of the mags. As far as one being bad, I don't think either one are bad. You will, however, get many differences of opinions on these two cartriges. There are thoes who like one or the other and just as many who don't for one reason or another.