RE: H S Strut undertaker choke .665
I've got an older Browning BPS. It has the same choke system as your 1300. I got an Undertaker last year. It shot Win. HV #6's better than any other choke I tried so far. It shot #4's as well as any choke I've tried. It shoots as tight a pattern as I would want to shoot without adding sights to the shotgun.