Deep River has changed their rules as I referenced in the original post, which was the reason for the post. Using sub gauge tubes would reasonably allow myself and others the ability to shoot an additional 4 events at Deep River during the weekend without having to purchase an additional 20 and 28 gauge gun which makes it a lot more reasonable from a financial stand point.

How this ventured in to a LCSCA/PCGA rules discussion is completely unintentional on my part and doesn't answer the questions in the original post.