Todd,
I shoot a 835 and mine will put 300+ in a 10 inch circle with 3 1/2" Hevi-13 7's and the .670 Pure Gold choke. I killed a Merriam in South Dakota at a lasered 38 yards and the bird never moved when I pulled the trigger. 7's are hard to beat. I can't comment on Nitros because I've never tried them but several of the guys on here LOVE them. Here's the link to Colonial Arms that manufactures the Stardot
http://www.colonialarms.com/ct07.html You will want to order the Extra full for the 835, which will be .676. They are shooters with the Hevi-13 7's as well. Good Luck with your choice.