Have B Square adaptors on my CZ 455 and like 'em.
Not really any reason to use 'em on an RAR that I can think of, since it comes already D/T'd for #12 bases?
A rimfire sporter that isn't stainless, isn't of much use to me during our hot and humid summers, the time of year I am most likely to go afield with a rimfire rifle, so the RAR-rimfires haven't raised my interest. I haven't looked at them very closely and didn't know that they were factory d&t. For a d&t rimfire rifle, the chose of bases is pretty much limited to whatever bases the rifle is factory d&t for.