#4's are the only size I found in the Nitro's. Surprisingly though, they pattern better than the Winchester 3 1/2" 5's and 6's I shot.
All of my turkeys were shot with 6's except the last two years in which I used 5's. I've never had a gun that patterned well at all with 4's until my new 535. I would definitely use 5's or 6's in these shells if I could find them around here.
rw