If you want to use rifled slugs ( NOT SABOTS) you can use a modified or improved choke. Both of these have worked fine for me.

If you want to use sabots you can get a rifled choke from various makers, but my favorite is a Briley diffusion choke. It does me well at the range out to about 176 yds with partition golds. This is the furthest distance I have tried with this choke, because the rod and gun club was making renovations last season and the furthest I could shoot from the temporary range was 176 yds.