STS has been floating these rumors for some time now, and in my personal opinion, it's just sour grapes that Dan came out with a superior-looking product in the eyes of many at a very reasonable price. Everything I've heard is that they don't have any room to shut him or anyone else down in the marketplace; their patent is way too vague and generic. I would be inclined to believe that, or else they'd also be able to shut down Hoyt and Ross for their stock suppressors on some of their offerings.