While I know nothing of the pending 45acp offering . I can tell you this . I own both the R9 and a AMT Backup 45 acp . You would be amazed at how small the AMT is next to the R9 . With this in mind . I would guess that if Rohrbaugh puts out a 45 acp . It may mimic the size envelope of the AMT . That pistol is about 10% larger overall then the R9 . Even with current CNC processes . I would think that a new R-45 could not be any smaller . I measure my AMT at about 5 3/4" long by about 4" high . At 24 oz . It is near double the R9 weight and has a 5 shot magazine . While at the time in the early 1990s . I carried it because it was the smallest 45 auto around . But I feel the R9 purpose is a size , weight , caliber mix done right ! I found the AMT 45 was to heavy for true pocket / ankle carry . So it would ride in an IWB setup . The R9 is a dream in ANY mode or carry .
Would I buy an R-45 today ? It would have to have sights , be lighter . smaller and around the same price as the R9 is today . But I would still slip the R9 in my pocket and feel ARMED for self protection . I hope you find this helpful .