Ordered this two days ago and it already arrived. Very fast service. The barrel and adapter are nice looking pieces of work. For the price, I believe it to be a best buy. As most of you know, the barrel has a groove cut into in the OD of the chamber area. The adapter has a ball detent that lock it in perfectly with the barrel. Really solid thinking on their part.
I am putting this together piece by piece as funds become available. It may end up costing me more in the long run, but that cannot be helped. Next purchase will be the upper receiver, For now, I am very satisfied with the items CMMG sent. I have the beginnings of a really nice .22 upper. Thanks guys.