From the date code in the picture, the pistol was made in 1971.
From the grip shape, it might be a Pietta; but could be ASM or one of the other unidentified makers of the period. As to current makers marks, date codes and proofmarks, the link Sir Charles provided will be of assistance to you. If the barrel markings have 'San Marco', 'Marco', 'ASM', or 'SM' in them, it was made by Armi San Marco. There are other markings that could be on the back strap that would indicate the maker.
Being a brass framed revolver. I would strenuously advise against useing any loads that exceed 25 grains of fffg blackpowder if you intend to keep it shootable for any length of time. Heavy loads will batter the recoil sheild and loosen the arbor in the frame resulting in excessive barrel cylinder gap and a gun that rattles like a marble in a paint can. Besides, you don't need more powder than that to hit what your aiming at.