Hi,
I used a 50-300mm many years ago. It was huge and heavy and not as sharp as my primes. It's not as sharp as the newer Nikon zooms. I agree with the suggestion about the 80-200mm f2.8.
That is a sharp lens. There are several variations so do your homework and read the reviews. On the cheap side, I am very happy with my 70-210mm AF-D f4-f5.6 Nikkor (does have an aperture ring). I originally bought it for my wife and was amazed how sharp and contrasty the images are. It's not built like a Gold Ring lens but for about $100 it's a keeper.
http://www.kenrockwell.com/nikon/7021056.htm
Rick