I think the Bullet is a 20th Century bullet , started being made about the 30's .
It was a cheap round and if I remember right it was called True Flight. We still have a box around somewhere
that my Great Grandfather had in his things when he passed away.
The shape of the crimp was supposed to make it fly straighter than the old flat bottom type rounds that where in use at that time.
I will look and see if I can find the box and take a photo , but I am not sure that it is where I am and may be in storage.
On the box it had a drawing of the old type bullet in a tumble in flight, and a drawing of this bullet in straight flight about to hit a rabbit!
The colors of ink was that faded blue that was used so much on items of that time.
It was a cheap off market round that was sold in the country stores of that time.
Now I am taking this from memory so I may be wrong on part, but I will do some searching, and this may give you a place to start looking.