Thanks @bigdog02 for the reply and the warm welcome. Yeah, I'm running the Mesa Tactical Urbino stock (here in California). I think the pic rail is pretty much a lost cause from what I'm reading and from chatting with the (very helpful) folks at Scalarworks (biased, I'm sure, but I feel honest nonetheless). So, I'm gonna retire the shell carrier with pic rail and get the Scalarwork + SRO combo. I'm sure it will be a worthwhile trade-off -- and, since I'm using a fixed stock, I can get a 6-shot carrier and mount to the stock (also from Mesa).