Mine has a 28" barrel. Tried a Winchester 3 1/2" #4 [a black shell] at 40 yds. the pattern was not very good. I used the full choke that came with the gun.
Would appreciate recommendations from anyone who has had good results with that gun.
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Federal (PFC157F) a 3" shell ,#6 with the flite control wad is the ticket for turkeys with my SBEII and the extra full choke. I've never tried the #4 shells.