I love the Nitros. They are 8 bucks apiece but shoot like a dream. I also like the Federal Heavyweights (I forget the real name but they are the high dollar Federals).

If you go to the Nitros Shotshells website you will find a page that gives the owners preferred shell/choke/gun combination. If I remember correctly the owner has tried every combination and can tell you which shells shoot best.

You may be able to talk to a local gun shop into buying some. One of the places near me sells them individually. They also have different size loads/shot so you can try a few different ones. I buy them as I need them and use the cheaper shells as a backer for the Nitros. I will load up 1 Nitro and put two cheaper shells behind it so I don't waste the high dollar suckers on follow up shots.