I don't know SDsuppressor or whoever retailer that is being talked about in this thread, but I don't think you guys should be shocked at a retailer having very little knowledge on these matters. I was told some pretty unreal things just the other day by a large volume dealer in our area. Things like incorrect SBR marking info, "just put stock on and don't worry about it", etc. His "expert" in house gunsmith told me forcefully that the Tirant did not adjust for indexing and no suppressor needs to adjust for indexing. My only point is most of the people in the NFA business know far less about the business they are a part of than the typical consumer on this board. I'd say a good 80% plus are full on dumb-asses.
By the way, I showed the gunsmith the instructions in the Tirant owners manual from their display case how to adjust the indexing. Didn't phase him one bit...Can't fix stupid as they say but is sure isn't a reflection on the quality of the product.