Help ID Brazilian .45 Auto Loading Type

I have a Brazilian .45 Auto cartridge loaded with standard GM FMJ RN bullet, but in a blackened case. It appears the case was blackened when it was already a new primed- empty case, as there is some “spill-over” of the blackening process to the brass “V”-marked primer cup (the “V” is flat bottomed, not pointed as I have to show here, and is a standard CBC primer marking). Headstamp is " - 45 AUTO - CBC".

My first thought is that it is a commercial proof round, but I have no documentation for that identification.

I do have a CBC .45 know proof round in my collection, but it has a purple base and bullet, and is a barrel-proof for the Brazilian copy of the US M3/M3A1 SMG.

Any positive identification will be appreciated.

John Moss