I have a 638 and a model 49. One or the other is my constant companion, and has been for several years now. I really like the "Bodyguard" J frames as they are snag free in the pocket and yet offer a single action shot if it is called for. I have not encountered a problem with the open hammer section getting clogged with pocket debris and not working, but I do carry them in a pocket holster and without anything else (change,etc.), in that pocket. I have not fired a .327 mag, but in the Airweight 638, 125 grain +P hollowpoints are about all I wish to touch off in such a small gun. I concur that a 649 would be a dandy thing to have!
Wakatomika