Rob Roberts and 870

[Bottomland]

Has anyone messed with this combo??? ive got a 870 sm and wondering what robs chokes will do in it.  Trying to find some info.

[Gooserbat]

I shot a ballistic specialties choke for over 15 Yeats out of an 870.  Hr designed it before he founded his own company, and what I understand they ate very close in design.  It shoot very good with any load I put through it.