This is my 1 1/2. I've had it for more than 25 years, it is in 32 RF caliber. The reason that the BB is different, is that I put in a CF block, not long after I got it. It's a BP block that I got from Bill Westcom, long before he sold is business to RB Ken. I still have the near perfect RF BB, too.
Through out the years, they have been, sort of a "Redheaded Step Child" of of single shots, in general. You don't see many of them, even on this forum.
The two basic differences between the #1 BP, RB and the #1 1/2 are the action width (about 1.15") and the barrel thread, at .850 (same as a #2).
De Haas says that they are good for the 32/40 & 38/55 and they probably are, based on the BB being the same as the #1, as well as the hammer and breech block pins. But, I always wanted to make mine into a 32 Ideal but, hasn't happened yet
Even though, these rifles are very rare, their value doesn't show that. I haven't priced them in a long time but, as last I knew, they are valued at about what a #2 is. What do collectors value them at now?
Since we don't get a chance to see them very often, I'd like to invite all that have one to post pictures of theirs, please.
Frank