D2 is correct, it is a Colt bullet. More specific ID... it was made in a Colt bulletmold, for use in a Colt .44-caliber Revolving Pistol. Your bullet is unfired. This version of Colt bullet is from the civil war era, but continued to be used for several tyears after the end of that war.
It has not been "carved on." The small short pointy projection on its base is the result of improper casting. Not quite enough molten lead was poured into the bulletmold (which casts the bullet nose-downward), resulting in what bullet-casters (and civil war bullet colelctors) call a "short-pour" bullet. I've seen it happen when casting lead bullets for my reproduction civil war Colt Revolver.
The photos below show a .44 Colt Patent bulletmold, with the opening for pouring lead into the mold cavity at its top. The other photo shows two "short-pour" Colt Dragoon bullets, dug by a civil war relic-hunter in a yankee encampment, which were discarded by the soldier who was casting bullets for his revolver. Apparently he didn't want to take the time to re-melt the flawed castings to re-use the lead.
