I have one of the older models without the ported barrel.In it I use a Star Dot .676 with winchester HV 3.5" #6.It does a fine job but not a GOOD 40 yard pattern.I have heard people say to use Hevi Shot and the Rhino 2" choke.They say it is outstanding.
The only downside is like sour01 says it will knock your shoulder off.
I now have an 1187 Supermag and it shoots better with half the recoil.