I have a Win 1200 32" scoped that will hold 4" IM choke
My Mossberg 500C 26" rifle sights will hold 6" IM choke
My Mossberg 9200 with 18 1/2" will hold 6" Full choke
Shooting from a rest which I would be shooting from at my deerstand.
This is 60 yards with the Win1200 offhand shooting as fast as I could pump another shell into the chamber and shoot. I don't remember anymore if it was Winchester, Remington or Fiocchi slugs but it doesn't matter because at 100 yards they all shoot close to the same point.
As long as you have at least an IC or M choke you should be able to duplicate that. If you aren't choked then you need to look for the oversize slugs or you won''t be consistent.