Got a Carcano round yesterday with the headstamp "T
The B is for Bologna, the factory/arsenal, and the TM are the initials of the government inspector there. I’m sure someone will post with the inspector’s name. I would bet that the date is 35, not 55.
A list of known and unknown Italian inspectors was on the thread "Italian Inspector S.A, posted December 27, 2008 at 3:08 PM.
I don’t know how to do the direct click on it link, but you should be able to find it quickly with the above. I found it quickly searching only “initials.”
T.M. is unknown. The date on your Carcano cartridge must be “35” as John says, and not “55.”
I hope that this link can be also useful to you for new recoveries