IIRC, the BSS was intended to be the new SXS for those whose old ones were turning into collector's items rather than field guns.
Buddy had a 20 gauge, very nice little shooter for the uplands. Hard kicker with 3" mags, but what 6 1/4 lb shotgun isn't?
I believe SKB made these,and there was a matching SXS in the SKB catalog at one time...