I have owned a lot of guns that use the berreta benelli mobile chokes. Best place to start is go tight due to I.D. of barrel.These guns are tighter bore than say a remington. All my mobile choke guns like a .640-.655 with any shell. Best lead chokes are .640-.650. HTL i run .650-.655. I have had great luck with carlson tubes and they are only $25-$30 and made in USA. I shot a .655 jellyhead in one gun and it did great.The little primos tightwad is another that shouldnt be overlooked. Hope this helps.