I've had one since sometime in the late 70's. It's a BL-4. Mine has a 26" barrel choked skeet/skeet with a wide rib.
It's still my favorite shotgun although I've stopped using it on sporting clays and moved to a heavier Beretta
after shoulder surgery. Primarily my pheasant and grouse gun since I don't take long shots and hunt with a dog.
It's been absolutely trouble free.
From what I've been able to gather parts are pretty much non-existent. Certainly a consideration if you are considering purchasing one.
Like I said mine has been trouble free but if I were considering a shotgun now I think I'd lean towards a 800 series unless the price and condition
of the BL were really right. The 800 series have had a longer run than the BL's and they're still around.