The rifling job is around 150. I chose the twist because years ago I had a barrel cut by Les Bauska in 20ga. I asked for a 66 twist and it ended up grouping Brennekes into 2.5 and Lightfields into 1.5 at 100.
If I go with a faster twist I presume that it could add to the utility with sabots but If I don't shoot full bore slugs I may go with round balls.

Thanks and Happy New Year.

Tom