I just had a ultra slug barrel fitted to my nef 10 ga. but i still use my Ithaca model 37 with a deerslayer barrel , smoothbore imp.cylinder. I use winchester 2 3/4" rifled slugs at 1600 fps. Dead on at 50 yds with a2" group at most and only a 3" drop at 100yds with a 4"group(at most)