Originally I had a 3x9 40m Banner scope on my NEF, but found that it was too much scope for the conditions I hunted in. Here in Virginia the brush can be nasty, so your shots are limited to under 100 or even 75 yards in most cases. I ended up going to a Tasco Bantam 2.5x scope. It is perfect for these conditions. I used a Weaver base and Weaver 4x4 rings. I did however go with the offset 4x4 rings and it gave me a better eye relief:
This setup is very comfortable and very effective in my hunting area. I shoot a 300grain XTP sabot with 85 grs of black powder. So far it has taken deer every season for the last four years. Funny part is my buddy uses the gun, because he doesn't have a BP gun. I think he is just too lazy and cheap to go out and buy one for himself. Did I forget to say that I hunt on his property?